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https://issues.apache.org/jira/browse/HDFS-7955?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15121287#comment-15121287
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Rakesh R commented on HDFS-7955:
--------------------------------
Thanks [~drankye] for the interest and comments.
With this jira, the idea is to re-visit the whole block recovery logic - both
EC recovery and re-replication part. Both these are rebuilding/repairing a lost
block and have suggested to use the word reconstruction in that sense. But I
could see changing the entire block recovery will not be backward compatible as
it involves renaming the protocol layer entities. Also, I feel we could still
keep the word like striped to differentiate with the contiguous block.
Probably we need to discuss more and get the opinion from others as well.
{code}
Non-compatible changes like,
DatanodeProtocol.proto {
//...
BlockRecoveryCommand = 2;
BlockECRecoveryCommand = 9;
//...
}
InterDatanodeProtocol.proto {
//...
//...
/**
* Initialize recovery of a replica
*/
rpc initReplicaRecovery(InitReplicaRecoveryRequestProto)
returns(InitReplicaRecoveryResponseProto);
//...
//...
}
{code}
> Improve naming of classes, methods, and variables related to block
> replication and recovery
> -------------------------------------------------------------------------------------------
>
> Key: HDFS-7955
> URL: https://issues.apache.org/jira/browse/HDFS-7955
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: erasure-coding
> Reporter: Zhe Zhang
> Assignee: Rakesh R
> Attachments: HDFS-7955-001.patch, HDFS-7955-002.patch,
> HDFS-7955-003.patch
>
>
> Many existing names should be revised to avoid confusion when blocks can be
> both replicated and erasure coded. This JIRA aims to solicit opinions on
> making those names more consistent and intuitive.
> # In current HDFS _block recovery_ refers to the process of finalizing the
> last block of a file, triggered by _lease recovery_. It is different from the
> intuitive meaning of _recovering a lost block_. To avoid confusion, I can
> think of 2 options:
> #* Rename this process as _block finalization_ or _block completion_. I
> prefer this option because this is literally not a recovery.
> #* If we want to keep existing terms unchanged we can name all EC recovery
> and re-replication logics as _reconstruction_.
> # As Kai [suggested |
> https://issues.apache.org/jira/browse/HDFS-7369?focusedCommentId=14361131&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14361131]
> under HDFS-7369, several replication-based names should be made more generic:
> #* {{UnderReplicatedBlocks}} and {{neededReplications}}. E.g. we can use
> {{LowRedundancyBlocks}}/{{AtRiskBlocks}}, and
> {{neededRecovery}}/{{neededReconstruction}}.
> #* {{PendingReplicationBlocks}}
> #* {{ReplicationMonitor}}
> I'm sure the above list is incomplete; discussions and comments are very
> welcome.
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