[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=1386#comment-1386
]
Sebastien Barnoud commented on HDFS-11402:
--
Distcp with snapshot will report a rename when an open file is renamed from its
temporary name (as open file) to its final name.
Then it will only replicate this rename operation.
If we exclude open files based on some naming convention, we still have a non
working distcp in snapshot diff mode, because the data hasn’t been replicated
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>Priority: Major
> Fix For: 2.9.0, 3.0.0-alpha4
>
> Attachments: HDFS-11402-branch-2.01.patch, HDFS-11402.01.patch,
> HDFS-11402.02.patch, HDFS-11402.03.patch, HDFS-11402.04.patch,
> HDFS-11402.05.patch, HDFS-11402.06.patch, HDFS-11402.07.patch,
> HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=1177#comment-1177
]
Wei-Chiu Chuang commented on HDFS-11402:
[~Sebastien Barnoud]
bq. What if dfs.namenode.snapshot.capture.openfiles is false? We still have the
previous behavior and lose data with distcp in snapshot diff mode.
When its off it follows the previous behavior.
bq. Is there a way, to exclude open files from the snapshot when
dfs.namenode.snapshot.capture.openfiles is false?
You can exclude files in distcp if you know the file name pattern of those
files.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>Priority: Major
> Fix For: 2.9.0, 3.0.0-alpha4
>
> Attachments: HDFS-11402-branch-2.01.patch, HDFS-11402.01.patch,
> HDFS-11402.02.patch, HDFS-11402.03.patch, HDFS-11402.04.patch,
> HDFS-11402.05.patch, HDFS-11402.06.patch, HDFS-11402.07.patch,
> HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=1176#comment-1176
]
Wei-Chiu Chuang commented on HDFS-11402:
[~mark_christiaens] HDFS snapshot is consistent regardless of the immutable
feature enabled by this jira. HDFS snapshot is a NameNode-only operation, no
need for synchronization with DataNode so guaranteeing consistency is easy.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>Priority: Major
> Fix For: 2.9.0, 3.0.0-alpha4
>
> Attachments: HDFS-11402-branch-2.01.patch, HDFS-11402.01.patch,
> HDFS-11402.02.patch, HDFS-11402.03.patch, HDFS-11402.04.patch,
> HDFS-11402.05.patch, HDFS-11402.06.patch, HDFS-11402.07.patch,
> HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16662145#comment-16662145
]
Sebastien Barnoud commented on HDFS-11402:
--
To more precise, they are 2 usage of snapshots:
1) Retrieve files has they where at the snapshot date =>
dfs.namenode.snapshot.capture.openfiles=true
2) Distcp in snapshot diff mode
=> if dfs.namenode.snapshot.capture.openfiles=true the same open file may be
copied multiple times (for example flume sync target in append mode), which may
not be expected
In that case, we need to exclude open files from the snapshot, else the diff
won't reports any difference between snapshots and leads to data lose on the
target of the distcp.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>Priority: Major
> Fix For: 2.9.0, 3.0.0-alpha4
>
> Attachments: HDFS-11402-branch-2.01.patch, HDFS-11402.01.patch,
> HDFS-11402.02.patch, HDFS-11402.03.patch, HDFS-11402.04.patch,
> HDFS-11402.05.patch, HDFS-11402.06.patch, HDFS-11402.07.patch,
> HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16662047#comment-16662047
]
Sebastien Barnoud commented on HDFS-11402:
--
What if dfs.namenode.snapshot.capture.openfiles is false? We still have the
previous behavior and lose data with distcp in snapshot diff mode.
Is there a way, to exclude open files from the snapshot when
dfs.namenode.snapshot.capture.openfiles is false?
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>Priority: Major
> Fix For: 2.9.0, 3.0.0-alpha4
>
> Attachments: HDFS-11402-branch-2.01.patch, HDFS-11402.01.patch,
> HDFS-11402.02.patch, HDFS-11402.03.patch, HDFS-11402.04.patch,
> HDFS-11402.05.patch, HDFS-11402.06.patch, HDFS-11402.07.patch,
> HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16346473#comment-16346473
]
Mark Christiaens commented on HDFS-11402:
-
I'm curious whether this fix now guarantees _consistent_ snapshots. By
consistent I mean, when a snapshot is taken, all files, (open or otherwise)
should be recorded in the snapshot at "the same" time. (I know, that "at the
same time" is not well-defined in a distributed system so something like
"causally consistent" is probably more accurate.) I guess my question is, what
are the consistency guarantees of the snapshot?
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>Priority: Major
> Fix For: 2.9.0, 3.0.0-alpha4
>
> Attachments: HDFS-11402-branch-2.01.patch, HDFS-11402.01.patch,
> HDFS-11402.02.patch, HDFS-11402.03.patch, HDFS-11402.04.patch,
> HDFS-11402.05.patch, HDFS-11402.06.patch, HDFS-11402.07.patch,
> HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16059791#comment-16059791
]
Manoj Govindassamy commented on HDFS-11402:
---
Thanks [~brahmareddy]. Updated the release notes.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Fix For: 3.0.0-alpha4
>
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch, HDFS-11402.07.patch, HDFS-11402.08.patch,
> HDFS-11402-branch-2.01.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16059705#comment-16059705
]
Brahma Reddy Battula commented on HDFS-11402:
-
Outstanding snapshot inconsistency is addressed by this.nice work.(y).looks
release notes is not updated,it's better to update release notes.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Fix For: 3.0.0-alpha4
>
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch, HDFS-11402.07.patch, HDFS-11402.08.patch,
> HDFS-11402-branch-2.01.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15979740#comment-15979740
]
Hudson commented on HDFS-11402:
---
SUCCESS: Integrated in Jenkins build Hadoop-trunk-Commit #11623 (See
[https://builds.apache.org/job/Hadoop-trunk-Commit/11623/])
HDFS-11402. HDFS Snapshots should capture point-in-time copies of OPEN (yzhang:
rev 20e3ae260b40cd6ef657b2a629a02219d68f162f)
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshotDiffReport.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/LeaseManager.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirSnapshotOp.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeDirectory.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestLeaseManager.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodesInPath.java
* (edit) hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshotManager.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/SnapshotManager.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestOpenFilesWithSnapshot.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogLoader.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/DirectorySnapshottableFeature.java
* (edit)
hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/HdfsClientConfigKeys.java
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Fix For: 3.0.0-alpha3
>
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch, HDFS-11402.07.patch, HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{Fi
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15979739#comment-15979739
]
Yongjun Zhang commented on HDFS-11402:
--
We might consider backport to branch-2. The jira is marked incompatible, but
the new behaviour is disabled by default. It should be safe to put into
branch-2 so people can enable it when they need it.
BTW, noticed a small thing
{quote}
If true, snapshots taken will have an immutable shared copy of
{quote}
The "shared" word in hdfs-default.xml looks a bit confusing. We indeed create a
copy and it's not really shared, maybe we can remove this word later.
Thanks.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Fix For: 3.0.0-alpha3
>
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch, HDFS-11402.07.patch, HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15979738#comment-15979738
]
Yongjun Zhang commented on HDFS-11402:
--
Committed to trunk. Thanks [~manojg] for the very good contribution!
And thanks [~jingzhao] [~andrew.wang] for the view!
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Fix For: 3.0.0-alpha3
>
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch, HDFS-11402.07.patch, HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15979731#comment-15979731
]
Yongjun Zhang commented on HDFS-11402:
--
Thanks [~andrew.wang] for the review, I did another round of review, looks good
to me too. +1.
I'm going to commit soon.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch, HDFS-11402.07.patch, HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15979577#comment-15979577
]
Manoj Govindassamy commented on HDFS-11402:
---
Above unit test failures not related to the patch.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch, HDFS-11402.07.patch, HDFS-11402.08.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15979574#comment-15979574
]
Hadoop QA commented on HDFS-11402:
--
| (x) *{color:red}-1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m
26s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s{color} | {color:green} The patch appears to include 4 new or modified test
files. {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
9s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 14m
31s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
36s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
50s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
30s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
30s{color} | {color:green} trunk passed {color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red} 1m
25s{color} | {color:red} hadoop-hdfs-project/hadoop-hdfs-client in trunk has 2
extant Findbugs warnings. {color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red} 1m
39s{color} | {color:red} hadoop-hdfs-project/hadoop-hdfs in trunk has 10 extant
Findbugs warnings. {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
3s{color} | {color:green} trunk passed {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
7s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
24s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
24s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m
24s{color} | {color:green} the patch passed {color} |
| {color:orange}-0{color} | {color:orange} checkstyle {color} | {color:orange}
0m 47s{color} | {color:orange} hadoop-hdfs-project: The patch generated 2 new +
788 unchanged - 4 fixed = 790 total (was 792) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
25s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
26s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} xml {color} | {color:green} 0m
1s{color} | {color:green} The patch has no ill-formed XML file. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
18s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
1s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 1m
12s{color} | {color:green} hadoop-hdfs-client in the patch passed. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 95m 31s{color}
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
20s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}132m 9s{color} |
{color:black} {color} |
\\
\\
|| Reason || Tests ||
| Failed junit tests | hadoop.hdfs.server.datanode.TestDataNodeHotSwapVolumes |
| | hadoop.hdfs.server.namenode.ha.TestHAAppend |
| Timed out junit tests |
org.apache.hadoop.hdfs.server.blockmanagement.TestBlockStatsMXBean |
\\
\\
|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:0ac17dc |
| JIRA Issue | HDFS-11402 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12864572/HDFS-11402.07.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle xml |
| uname | Linux ed52ac537083 3.13.0-108-generic #155-Ubuntu SMP Wed Jan 11
16:58:52 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personalit
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15979544#comment-15979544
]
Andrew Wang commented on HDFS-11402:
I discussed offline with Manoj on the stride, he's going to make a rev.
Otherwise looks good to me!
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch, HDFS-11402.07.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15977967#comment-15977967
]
Andrew Wang commented on HDFS-11402:
Hi Manoj, took another look, mostly just code cleanup-type comments. Would also
be interested to know how you chose 512 inodes/thread as it seems like a magic
number, was this based on benchmarking?
bq. the byte[][] is already available getINodesAndPaths() along with INode[].
Wouldn't it be a lot slower to have one more helper method to construct the
same byte[][] ?
It seems equivalent if we have two functions as follows:
{noformat}
private static INode[] getINodes(final INode inode) {
int depth = 0, index;
INode tmp = inode;
while (tmp != null) {
depth++;
tmp = tmp.getParent();
}
INode[] inodes = new INode[depth];
tmp = inode;
index = depth;
while (tmp != null) {
index--;
inodes[index] = tmp;
tmp = tmp.getParent();
}
return inodes;
}
private static byte[][] getPaths(final INode[] inodes) {
byte paths[][] = new byte[inodes.length][];
for (int i=0; i> f: futureList) {
try {
iipSet.addAll(f.get());
} catch (Exception e) {
LOG.warn("INode filter task encountered exception: ", e);
}
}
{noformat}
Mind filing a JIRA to migrate LeaseManager over to SLF4J as well? We're adding
a pretty gnarly new log that would be more readable with SLF4j.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch,
> HDFS-11402.06.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15977924#comment-15977924
]
Hadoop QA commented on HDFS-11402:
--
| (x) *{color:red}-1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m
35s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s{color} | {color:green} The patch appears to include 4 new or modified test
files. {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
25s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 15m
40s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
27s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
48s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
26s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
28s{color} | {color:green} trunk passed {color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red} 1m
22s{color} | {color:red} hadoop-hdfs-project/hadoop-hdfs-client in trunk has 2
extant Findbugs warnings. {color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red} 1m
40s{color} | {color:red} hadoop-hdfs-project/hadoop-hdfs in trunk has 10 extant
Findbugs warnings. {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
4s{color} | {color:green} trunk passed {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
8s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
33s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
26s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m
26s{color} | {color:green} the patch passed {color} |
| {color:orange}-0{color} | {color:orange} checkstyle {color} | {color:orange}
0m 50s{color} | {color:orange} hadoop-hdfs-project: The patch generated 2 new +
788 unchanged - 4 fixed = 790 total (was 792) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
27s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
27s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} xml {color} | {color:green} 0m
2s{color} | {color:green} The patch has no ill-formed XML file. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
39s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
8s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 1m
20s{color} | {color:green} hadoop-hdfs-client in the patch passed. {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 94m
4s{color} | {color:green} hadoop-hdfs in the patch passed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
20s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}133m 6s{color} |
{color:black} {color} |
\\
\\
|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:0ac17dc |
| JIRA Issue | HDFS-11402 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12864389/HDFS-11402.06.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle xml |
| uname | Linux d142ce37debf 3.13.0-108-generic #155-Ubuntu SMP Wed Jan 11
16:58:52 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh
|
| git revision | trunk / f356f0f |
| Default Java | 1.8.0_121 |
| findbugs | v3.1.0-RC1 |
| findbugs |
https://builds.apache.org/job/PreCommit-HDFS-Build/19165/artifact/patchpr
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15977503#comment-15977503
]
Wei-Chiu Chuang commented on HDFS-11402:
One nit:
{code}
LOG.warn("INode filter task encountered exception: "+ e);
{code}
Please use LOG.warn(Object message, Throwable t) to preserve stacktrace.
In LeaseManager#getINodeWithLeases, It is a little counter-intuitive to me
that, assuming 4 worker threads, if there are 4 or less files with leases only
one worker thread is run, but if there are 5 files with leases, 4 worker
threads all run.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch, HDFS-11402.05.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15975935#comment-15975935
]
Hadoop QA commented on HDFS-11402:
--
| (x) *{color:red}-1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m
15s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s{color} | {color:green} The patch appears to include 4 new or modified test
files. {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
10s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 14m
44s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
39s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
53s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
41s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
31s{color} | {color:green} trunk passed {color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red} 1m
35s{color} | {color:red} hadoop-hdfs-project/hadoop-hdfs-client in trunk has 2
extant Findbugs warnings. {color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red} 2m
6s{color} | {color:red} hadoop-hdfs-project/hadoop-hdfs in trunk has 10 extant
Findbugs warnings. {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
14s{color} | {color:green} trunk passed {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
9s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
55s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 2m
2s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 2m
2s{color} | {color:green} the patch passed {color} |
| {color:orange}-0{color} | {color:orange} checkstyle {color} | {color:orange}
0m 56s{color} | {color:orange} hadoop-hdfs-project: The patch generated 4 new +
788 unchanged - 4 fixed = 792 total (was 792) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
55s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
27s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} xml {color} | {color:green} 0m
2s{color} | {color:green} The patch has no ill-formed XML file. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
57s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
14s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 1m
26s{color} | {color:green} hadoop-hdfs-client in the patch passed. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 81m 1s{color}
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
21s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}122m 12s{color} |
{color:black} {color} |
\\
\\
|| Reason || Tests ||
| Failed junit tests |
hadoop.hdfs.server.datanode.TestDataNodeVolumeFailureToleration |
| | hadoop.hdfs.server.datanode.TestDataNodeVolumeFailureReporting |
| | hadoop.hdfs.server.namenode.ha.TestPipelinesFailover |
| | hadoop.hdfs.TestDFSStripedOutputStreamWithFailure160 |
| | hadoop.hdfs.TestDFSStripedOutputStreamWithFailure120 |
\\
\\
|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:0ac17dc |
| JIRA Issue | HDFS-11402 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12864169/HDFS-11402.05.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle xml |
| uname | Linux 5e0352be5ef0 3.13.0-105-generi
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15969728#comment-15969728
]
Andrew Wang commented on HDFS-11402:
Hi Manoj, thanks for working on this. I gave it a nit pass, still thinking
about the high-level idea, but wanted to post this up before the weekend:
* typo: FRREZE -> FREEZE
* Maybe name it "dfs.namenode.snapshot.capture-file-length" to be more
explanatory?
* hdfs-default.xml: hflush/hsync also do not update the NN's view of the file
length unless the client calls hsync with a special flag.
INodesInPath
* Not a fan of Pair since it doesn't document its entries, could we instead add
a helper method that given an INode[] returns a byte[][]?
* We made an effort to avoid resolving paths -> IIPs and back during RPC
handling for performance reasons. This is a special case for the lease manager,
which only has an INode ID. Can you add a comment saying as much for the newly
added methods?
* isDescendant javadoc, could you reverse it to say "if this InodesInPath is a
descendant of the specified INodeDirectory"?
* the private isDescendant is only called by the public one, combine into one?
This way we don't lose the typesafety of the INodeDirectory also.
* isDescendant, if we're an IIP, can we simply look in our array of INodes for
the specified ancestor? This method looks expensive right now.
LeaseManager
* What are the locking requirements for the new methods? add asserts?
* Is the threading important for performance? Was this benchmarked? I suspect
it's slower for small numbers of open files.
* Can call {{shutdown}} immediately after adding all the futures to the
executor.
* Currently we swallow when a future.get throws an exception. If we return a
partial set, won't the snapshot be inaccurate?
* ancestorDir isn't mutated, so can we move the ancestorDir null check out of
the Callable?
* testCheckLease, why is there a new sleep(1)? Thread sleeps in a unit test are
a code smell.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS S
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15968082#comment-15968082
]
Wei-Chiu Chuang commented on HDFS-11402:
Hello [~manojg] Thanks for the patch.
I am stilling reviewing the patch, but I have a few quick comments if you don't
mind:
* Have you considered the case where an inode is a INodeReference? I haven't
thought about this hard enough, but would like to make sure we cover that case
well.
* How about we add some debug messages in {{LeaseManager#getINodeWithLeases}}.
E.g. the inode id or file name added in each thread.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15966788#comment-15966788
]
Manoj Govindassamy commented on HDFS-11402:
---
Above unit test failure is not related to the patch. Checkstyle issue is
regarding the method definition being longer than 150 lines.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch, HDFS-11402.04.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15966590#comment-15966590
]
Hadoop QA commented on HDFS-11402:
--
| (x) *{color:red}-1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 14m
4s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s{color} | {color:green} The patch appears to include 4 new or modified test
files. {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
28s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 15m
21s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
47s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
51s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
44s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
31s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
41s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
2s{color} | {color:green} trunk passed {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
7s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
22s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
27s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m
27s{color} | {color:green} the patch passed {color} |
| {color:orange}-0{color} | {color:orange} checkstyle {color} | {color:orange}
0m 49s{color} | {color:orange} hadoop-hdfs-project: The patch generated 2 new +
788 unchanged - 4 fixed = 790 total (was 792) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
26s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
24s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} xml {color} | {color:green} 0m
2s{color} | {color:green} The patch has no ill-formed XML file. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
25s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
58s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 1m
11s{color} | {color:green} hadoop-hdfs-client in the patch passed. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 96m 15s{color}
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
34s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}149m 4s{color} |
{color:black} {color} |
\\
\\
|| Reason || Tests ||
| Failed junit tests | hadoop.hdfs.TestMissingBlocksAlert |
| Timed out junit tests |
org.apache.hadoop.hdfs.server.blockmanagement.TestBlockStatsMXBean |
\\
\\
|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:612578f |
| JIRA Issue | HDFS-11402 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12863103/HDFS-11402.04.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle xml |
| uname | Linux 597321cc4deb 3.13.0-108-generic #155-Ubuntu SMP Wed Jan 11
16:58:52 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh
|
| git revision | trunk / d4c01dd |
| Default Java | 1.8.0_121 |
| findbugs | v3.0.0 |
| checkstyle |
https://builds.apache.org/job/PreCommit-HDFS-Build/19063/artifact/patchprocess/diff-checkstyle-hadoop-hdfs-project.txt
|
| unit |
https://bu
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15961666#comment-15961666
]
Manoj Govindassamy commented on HDFS-11402:
---
Above unit test failures are not related to the patch.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch,
> HDFS-11402.03.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15961664#comment-15961664
]
Hadoop QA commented on HDFS-11402:
--
| (x) *{color:red}-1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m
14s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s{color} | {color:green} The patch appears to include 4 new or modified test
files. {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
31s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 13m
7s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
23s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
51s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
25s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
26s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
7s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
1s{color} | {color:green} trunk passed {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
7s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
17s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
19s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m
19s{color} | {color:green} the patch passed {color} |
| {color:orange}-0{color} | {color:orange} checkstyle {color} | {color:orange}
0m 47s{color} | {color:orange} hadoop-hdfs-project: The patch generated 7 new +
788 unchanged - 4 fixed = 795 total (was 792) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
20s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
20s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} xml {color} | {color:green} 0m
1s{color} | {color:green} The patch has no ill-formed XML file. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
21s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
54s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 1m
7s{color} | {color:green} hadoop-hdfs-client in the patch passed. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 63m 59s{color}
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
19s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black} 98m 24s{color} |
{color:black} {color} |
\\
\\
|| Reason || Tests ||
| Failed junit tests |
hadoop.hdfs.server.datanode.TestDataNodeVolumeFailureReporting |
| | hadoop.hdfs.server.datanode.fsdataset.impl.TestFsDatasetImpl |
\\
\\
|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:a9ad5d6 |
| JIRA Issue | HDFS-11402 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12862553/HDFS-11402.03.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle xml |
| uname | Linux a1d2e9186ff6 3.13.0-107-generic #154-Ubuntu SMP Tue Dec 20
09:57:27 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh
|
| git revision | trunk / 2aa8967 |
| Default Java | 1.8.0_121 |
| findbugs | v3.0.0 |
| checkstyle |
https://builds.apache.org/job/PreCommit-HDFS-Build/19020/artifact/patchprocess/diff-checkstyle-hadoop-hdfs-project.txt
|
| unit |
https://
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15946165#comment-15946165
]
Yongjun Zhang commented on HDFS-11402:
--
Hi [~manojg],
Thanks a lot for your work here and very sorry for my delayed review.
The patch looks largely good to me. Below are some comments, mostly cosmetic.
1. We can put the parameters leaseManager and freezeOpenFiles together at the
API, since they are used together for an optional feature. For example in
INodeDirectory
{code}
public Snapshot addSnapshot(final LeaseManager leaseManager,
int id, String name, boolean freezeOpenFiles)
{code}
we can change it to
{code}
public Snapshot addSnapshot(int id, String name,
final LeaseManager leaseManager,
final boolean freezeOpenFiles)
{code}
2. share common code in the two {{INodesInPath$fromINode}} methods
3. change method name {{isAncestor}} to {{isDescendent}} in {{INodesInPath}}
4. In {{LeaseManager}},
* INODE_FILTER_WORKER_COUNT is only used in a single method, it's better not to
define it as public, and maybe we can just move it to the single method.
* change {{getINodeWithLeases(final INodeDirectory restrictFilesFromDir)}}
to {{getINodesWithLease(final INodeDirectory ancestorDir)}}
and javadoc the behavior when ancestorDir is null or not-null
* optionally, possibly just use the above COUNT as a cap, and have a way to
dynamically decide how big the thread pool is, especially when the number of
files open for write is small. This can be consider in the future when needed.
* add a private method (like {{getINodesInLease}} to wrap
{code}
synchronized (this) {
inodes = new INode[leasesById.size()];
for (long inodeId : leasesById.keySet()) {
inodes[inodeCount] = fsnamesystem.getFSDirectory().getInode(inodeId);
inodeCount++;
}
}
{code}
5. In hdfs-default.xml, add a note to describe that the file length captured in
snapshot for a file is what's recorded in NameNode, it may be shorter than what
the client has written. In order to capture the length the client has written,
the client need to call hflush/hsync on the file.
6. Suggest to add a test about snapshot diff.
HI [~jingzhao], wonder if you could help doing a review too. Much appreciated.
Thanks.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the o
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15903712#comment-15903712
]
Manoj Govindassamy commented on HDFS-11402:
---
[~yzhangal], Any review comments on the patch ? Please let me know your
thoughts.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15881300#comment-15881300
]
Manoj Govindassamy commented on HDFS-11402:
---
Thanks for sharing your views [~raviprak]. I will wait for others to review the
patch and share the comments. And, I would also prefer this jira _not_
dependent on HDFS-11435.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15879013#comment-15879013
]
Ravi Prakash commented on HDFS-11402:
-
I'm sorry I don't fully understand why we care about HDFS-11435. In fact it
makes heartbeat handling a lot slower and more complicated. And for what?
Slightly more updated length values in Snapshots (a relatively rare operation.)
If the DNs send back lengths of RBW every heartbeat, you'll still have to
choose the minimum length returned by at least {{dfs.namenode.replication.min}}
nodes. IMHO we should store in the snapshot the last minimum length that the NN
knows data has been written till. If that's the last block boundary, so be it.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15875349#comment-15875349
]
Manoj Govindassamy commented on HDFS-11402:
---
Filed HDFS-11435 - NameNode should track open for write files lengths more
frequent than on newer block allocations.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15872939#comment-15872939
]
Manoj Govindassamy commented on HDFS-11402:
---
Thanks for correcting me on the readers getting to know on the latest length.
SyncFlag.UPDATE_LENGTH also has saved us on many such cases. I still see
_making snapshots truly read-only_ and _file lengths for open files_ as
separate issues and the former one more alarming. Yes, fixing the second one
will make the solution more reliable and I can take it up in a new jira, if
everyone agrees.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15872794#comment-15872794
]
Jing Zhao commented on HDFS-11402:
--
bq. We have the same problem with parallel readers when there is an ongoing
write.
This is not true. The current DFSInputstream has the capability to talk to
datanodes and learn the current length.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15872785#comment-15872785
]
Manoj Govindassamy commented on HDFS-11402:
---
Thanks for the design review [~jingzhao]. Much appreciated.
bq. I think the key challenge here is how to let NN know the lengths of open
files...If we choose to record l_n in the snapshot, then later we may have risk
to lose data (from client's point of view).
We have the same problem with parallel readers when there is an ongoing write.
Readers reading the file will have no clue on the latest length or data. But
there is always {{SyncFlag.UPDATE_LENGTH}} and applications wanting to update
NN about their latest writes can do {{hsync()}} with the SyncFlag option. This
same existing method is helpful for Snapshots also, as in the above case the
open file length captured in the snapshot would be the last hsync() length.
Otherwise, applications which are attempting to ensure consistent lengths of
files in HDFS snapshots will not be able to reliably do so. IMHO, HDFS Snapshot
is violating the important design goal of {{read-only}} behavior, as files in
the snapshot grow in size after the snapshot time. This mutable snapshot
behavior makes HDFS Snapshots far less attractive and applications not able to
make use of the feature in an useful way.
bq. I think we first need to solve the problem about how to report the length
of open files to NN (e.g., maybe utilizing the DN heartbeats or some other
ways).
I can dig deeper on this model to make HDFS Snapshots much more reliable. Given
that applications are already aware of NN length issues for open files, and the
availability of {{hsync(SyncFlag.UPDATE_LENGTH)}} to close the same gap, and
the proposed design is under a config which is turned off by default, do we
still need to make this jira a dependent on _fixing open file lengths via
heartbeat_ improvement ? Would love to hear your thoughts on this.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapsho
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15872739#comment-15872739
]
Jing Zhao commented on HDFS-11402:
--
Thanks for working on this, [~manojg]. Yes the length of open files is a known
issue for the current snapshot implementation. As you mentioned in the
description, the current semantic is to capture a length in snapshot which is
>= the real length when the snapshot was created. This behavior kind of breaks
the read-only semantic.
I think the key challenge here is how to let NN know the lengths of open files.
Currently the length of an open file is updated on the NN only when 1) the
first time hflush is called, or 2) hflush/hsync is called along with the
UPDATE_LENGTH flag. Thus if a file is being written, the file length on the NN
side (let's call it {{l_n}}) is usually a lot less than the length seen by the
DN/client.
If we choose to record {{l_n}} in the snapshot, then later we may have risk to
lose data (from client's point of view). E.g., a user wrote 100MB data and took
a snapshot. The {{l_n}} at that time might be only 1MB or even 0. Later if the
user deletes the file she will expect ~100MB still kept in the snapshotted
file, instead of 1MB or an empty file. At this time, from the safety point of
view, maybe the semantic of the current snapshot implementation is better.
So before we update the NN side logic about capturing the file length in
snapshots, I think we first need to solve the problem about how to report the
length of open files to NN (e.g., maybe utilizing the DN heartbeats or some
other ways).
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch, HDFS-11402.02.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_di
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15871185#comment-15871185
]
Hadoop QA commented on HDFS-11402:
--
| (/) *{color:green}+1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m
11s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s{color} | {color:green} The patch appears to include 3 new or modified test
files. {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
7s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 12m
27s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
21s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
39s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
22s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
25s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
7s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m
0s{color} | {color:green} trunk passed {color} |
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
7s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
18s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
18s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m
18s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
37s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
18s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
21s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} xml {color} | {color:green} 0m
2s{color} | {color:green} The patch has no ill-formed XML file. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 3m
15s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
54s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 0m
54s{color} | {color:green} hadoop-hdfs-client in the patch passed. {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 63m
41s{color} | {color:green} hadoop-hdfs in the patch passed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
19s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black} 96m 7s{color} |
{color:black} {color} |
\\
\\
|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:a9ad5d6 |
| JIRA Issue | HDFS-11402 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12853200/HDFS-11402.02.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle xml |
| uname | Linux c91ae938b25f 3.13.0-107-generic #154-Ubuntu SMP Tue Dec 20
09:57:27 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh
|
| git revision | trunk / 02c5494 |
| Default Java | 1.8.0_121 |
| findbugs | v3.0.0 |
| Test Results |
https://builds.apache.org/job/PreCommit-HDFS-Build/18393/testReport/ |
| modules | C: hadoop-hdfs-project/hadoop-hdfs-client
hadoop-hdfs-project/hadoop-hdfs U: hadoop-hdfs-project |
| Console output |
https://builds.apache.org/job/PreCommit-HDFS-Build/18393/console |
| Powered by | Apache Yetus 0.5.0-SNAPSHOT http://yetus.apache.org |
This message was automatically generated.
> HDFS S
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15870619#comment-15870619
]
Manoj Govindassamy commented on HDFS-11402:
---
Thanks for the review [~linyiqun].
I can split {{LeaseManager#leasesById}} Map entries into few parts and spin off
the {{LeaseManager#getINodeWithLeases()}} work in fixed thread pool Executor
and have them run in parallel. Each _Task_ will filter the open files from its
list and we can benefit from many such tasks running in parallel. Your thoughts
on this please ?
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15869832#comment-15869832
]
Yiqun Lin commented on HDFS-11402:
--
Hi, [~manojg], thanks for the work on this.
I just take a quick look on this, some comments from me. I am also concerning
the run time problem for this. Yes, you have mentioned that
{{LeaseManager#getINodeWithLeases()}} will return set of open files in
INodesInPath format under given {{INodeDirectory}}. And it will not deal with
all the open files. But I looked into this method, it seems this operation is
still expensive. The {{getInode}} and {{ INodesInPath#fromINode}} are still
executed whether the file is under given directory or not. So if the open files
is much enough, this method looks still expensive operation, right? How do you
think?
{code}
public Set getINodeWithLeases(final INodeDirectory
+ restrictFilesFromDir) {
+Set iNodeSet = new HashSet<>();
+for (final long iNodeId : leasesById.keySet()) {
+ INode inode = fsnamesystem.getFSDirectory().getInode(iNodeId);
+ assert inode.isFile();
+ INodesInPath iNodesInPath = INodesInPath.fromINode(
+ fsnamesystem.getFSDirectory().getRoot(), inode.asFile());
+ if (restrictFilesFromDir != null &&
+ !iNodesInPath.isAncestor(restrictFilesFromDir)) {
+continue;
+ }
+ iNodeSet.add(iNodesInPath);
+}
+return iNodeSet;
+ }
{code}
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
> Attachments: HDFS-11402.01.patch
>
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.op
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15869330#comment-15869330
]
Hadoop QA commented on HDFS-11402:
--
| (x) *{color:red}-1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m
35s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s{color} | {color:green} The patch appears to include 3 new or modified test
files. {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 16m
56s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
58s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
43s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
13s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
18s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 1m
59s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
49s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
11s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
0s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m
0s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
40s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
5s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
14s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 1m
59s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
39s{color} | {color:green} the patch passed {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 92m 42s{color}
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
27s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}124m 49s{color} |
{color:black} {color} |
\\
\\
|| Reason || Tests ||
| Failed junit tests | hadoop.tools.TestHdfsConfigFields |
| | hadoop.hdfs.TestRollingUpgrade |
| | hadoop.hdfs.server.datanode.TestDataNodeVolumeFailureReporting |
\\
\\
|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:a9ad5d6 |
| JIRA Issue | HDFS-11402 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12852975/HDFS-11402.01.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle |
| uname | Linux 043c43761295 3.13.0-107-generic #154-Ubuntu SMP Tue Dec 20
09:57:27 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh
|
| git revision | trunk / a136936 |
| Default Java | 1.8.0_121 |
| findbugs | v3.0.0 |
| unit |
https://builds.apache.org/job/PreCommit-HDFS-Build/18386/artifact/patchprocess/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt
|
| Test Results |
https://builds.apache.org/job/PreCommit-HDFS-Build/18386/testReport/ |
| modules | C: hadoop-hdfs-project/hadoop-hdfs U:
hadoop-hdfs-project/hadoop-hdfs |
| Console output |
https://builds.apache.org/job/PreCommit-HDFS-Build/18386/console |
| Powered by | Apache Yetus 0.5.0-SNAPSHOT http://yetus.apache.org |
This message was automatically generated.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improv
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15869091#comment-15869091
]
Manoj Govindassamy commented on HDFS-11402:
---
[~yzhangal],
LeaseManager maintains INodeFileIDs of all leased open files in-memory.
Moreover, with the proposed design LeaseManager now exposes a functionality to
get all files with leases under the given directory. So at the time of
Snapshot, the SnapshotManager will only run extra operations for the open files
under the snapshot dir and not on all the open files in the system. For all the
open files, creation of diff record is very light weight as it only copies the
length field from the file and not blocks.
Your proposal of maintaining diff record for each open file at the time of file
length update well before the Snaoshot is _not_ going to make the overall time
complexity O(1). The diff record computation is not the one contributing to the
extra time consumption at the Snapshot time. Its the generation of open files
under the snapshot directory and the diff record saving for each of those open
files is making the overall complexity for the snapshot creation an O(open
files count under snap root). And, {{dfs.namenode.snapshot.freeze.openfiles}}
config is {{false}} by default. Users who are interested in this feature can
enable this at a marginal cost and otherwise there aren't any performance dips
in the normal snapshot operation.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15861566#comment-15861566
]
Yongjun Zhang commented on HDFS-11402:
--
Hi [~manojg],
Thanks for working on this issue.
I share the same concern of run time, especially when handling many open files.
It may hold the FS lock for too long thus impacting NN service. If we can
distribute the burden to relevant file operation, then it would have less
runtime impact.
Wonder if it's possible to do the following, when NN updates the size of a
file, it calls INodeFile#recordModification to either create a new snapshotCopy
in FileDiff, or modify an existing snapshotCopy in FileDiff? If we can do this,
then we can still maintain o(1) time. The tricky thing is about modifying an
existing snapshotCopy of the file in FileDiff. The current code may not support
it, but it'd be nice to try to see if making some changes can make it work.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Commented] (HDFS-11402) HDFS Snapshots should capture point-in-time copies of OPEN files
[
https://issues.apache.org/jira/browse/HDFS-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15860275#comment-15860275
]
Manoj Govindassamy commented on HDFS-11402:
---
Hi [~andrew.wang], [~yzhangal], [~jingzhao],
Can you please take a look at the problem statement and the proposal above ?
Any comments/suggestions are welcome.
> HDFS Snapshots should capture point-in-time copies of OPEN files
>
>
> Key: HDFS-11402
> URL: https://issues.apache.org/jira/browse/HDFS-11402
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
>Affects Versions: 2.6.0
>Reporter: Manoj Govindassamy
>Assignee: Manoj Govindassamy
>
> *Problem:*
> 1. When there are files being written and when HDFS Snapshots are taken in
> parallel, Snapshots do capture all these files, but these being written files
> in Snapshots do not have the point-in-time file length captured. That is,
> these open files are not frozen in HDFS Snapshots. These open files
> grow/shrink in length, just like the original file, even after the snapshot
> time.
> 2. At the time of File close or any other meta data modification operation on
> these files, HDFS reconciles the file length and records the modification in
> the last taken Snapshot. All the previously taken Snapshots continue to have
> those open Files with no modification recorded. So, all those previous
> snapshots end up using the final modification record in the last snapshot.
> Thus after the file close, file lengths in all those snapshots will end up
> same.
> Assume File1 is opened for write and a total of 1MB written to it. While the
> writes are happening, snapshots are taken in parallel.
> {noformat}
> |---Time---T1---T2-T3T4-->
> |---Snap1--Snap2-Snap3--->
> |---File1.open---write-write---close->
> {noformat}
> Then at time,
> T2:
> Snap1.File1.length = 0
> T3:
> Snap1.File1.length = 0
> Snap2.File1.length = 0
>
> T4:
> Snap1.File1.length = 1MB
> Snap2.File1.length = 1MB
> Snap3.File1.length = 1MB
> *Proposal*
> 1. At the time of taking Snapshot, {{SnapshotManager#createSnapshot}} can
> optionally request {{DirectorySnapshottableFeature#addSnapshot}} to freeze
> open files.
> 2. {{DirectorySnapshottableFeature#addSnapshot}} can consult with
> {{LeaseManager}} and get a list INodesInPath for all open files under the
> snapshot dir.
> 3. {{DirectorySnapshottableFeature#addSnapshot}} after the Snapshot creation,
> Diff creation and updating modification time, can invoke
> {{INodeFile#recordModification}} for each of the open files. This way, the
> Snapshot just taken will have a {{FileDiff}} with {{fileSize}} captured for
> each of the open files.
> 4. Above model follows the current Snapshot and Diff protocols and doesn't
> introduce any any disk formats. So, I don't think we will be needing any new
> FSImage Loader/Saver changes for Snapshots.
> 5. One of the design goals of HDFS Snapshot was ability to take any number of
> snapshots in O(1) time. LeaseManager though has all the open files with
> leases in-memory map, an iteration is still needed to prune the needed open
> files and then run recordModification on each of them. So, it will not be a
> strict O(1) with the above proposal. But, its going be a marginal increase
> only as the new order will be of O(open_files_under_snap_dir). In order to
> avoid HDFS Snapshots change in behavior for open files and avoid change in
> time complexity, this improvement can be made under a new config
> {{"dfs.namenode.snapshot.freeze.openfiles"}} which by default can be
> {{false}}.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
-
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
