[
https://issues.apache.org/jira/browse/HDFS-2486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13205164#comment-13205164
]
Hudson commented on HDFS-2486:
------------------------------
Integrated in Hadoop-Mapreduce-trunk-Commit #1718 (See
[https://builds.apache.org/job/Hadoop-Mapreduce-trunk-Commit/1718/])
HDFS-2486. Remove unnecessary priority level checks in
UnderReplicatedBlocks. Contributed by Uma Maheswara Rao G
szetszwo :
http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1242636
Files :
* /hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
*
/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/UnderReplicatedBlocks.java
> Review issues with UnderReplicatedBlocks
> ----------------------------------------
>
> Key: HDFS-2486
> URL: https://issues.apache.org/jira/browse/HDFS-2486
> Project: Hadoop HDFS
> Issue Type: Task
> Components: name-node
> Affects Versions: 0.23.0
> Reporter: Steve Loughran
> Assignee: Uma Maheswara Rao G
> Priority: Minor
> Fix For: 0.24.0
>
> Attachments: HDFS-2486.patch
>
>
> Here are some things I've noted in the UnderReplicatedBlocks class that
> someone else should review and consider if the code is correct. If not, they
> are easy to fix.
> remove(Block block, int priLevel) is not synchronized, and as the inner
> classes are not, there is a risk of race conditions there.
> some of the code assumes that getPriority can return the value LEVEL, and if
> so does not attempt to queue the blocks. As this return value is not
> currently possible, those checks can be removed.
> The queue gives priority to blocks whose replication count is less than a
> third of its expected count over those that are "normally under replicated".
> While this is good for ensuring that files scheduled for large replication
> are replicated fast, it may not be the best strategy for maintaining data
> integrity. For that it may be better to give whichever blocks have only two
> replicas priority over blocks that may, for example, already have 3 out of 10
> copies in the filesystem.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
