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https://issues.apache.org/jira/browse/HDFS-7955?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15159765#comment-15159765
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Zhe Zhang commented on HDFS-7955:
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bq. Yeah, will start with BlockManager entities, UnderReplicatedBlocks =>
LowRedundancyBlocks, PendingReplicationBlocks => PendingReconstructionBlocks,
neededReplications => neededReconstruction, excessReplicateMap =>
extraRedundancyMap
Thanks [~rakeshr], LGTM
bq. I hope you are suggesting to deprecate dfs#getUnderReplicatedBlocksCount()
and add new API dfs#getLowRedundancyBlockCount(). Again we need to consider
FSNamesystemMBean metrics UnderReplicatedBlocks, PendingReplicationBlocks,
scheduledReplicationBlocksCount etc. Also, requires changes in DFSAdmin -report
basic filesystem information and fsck#ReplicationResult commands output.
The {{getUnderReplicatedBlocksCount}} API is used by upper layer apps quite
heavily, so deprecating it looks risky. I think we can leave this discussion
open for a longer window to solicit feedbacks.
> 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: Improvement
> Components: erasure-coding
> Reporter: Zhe Zhang
> Assignee: Rakesh R
> Attachments: HDFS-7955-001.patch, HDFS-7955-002.patch,
> HDFS-7955-003.patch, HDFS-7955-004.patch, HDFS-7955-5.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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