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https://issues.apache.org/jira/browse/HDFS-7369?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14361176#comment-14361176
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Zhe Zhang commented on HDFS-7369:
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Thanks for the review Kai!
# Naming: Thanks for bringing it up. I thought about it but found there are
many more places to change (listed below). We should have a separate JIRA to
discuss and handle that.
#* {{UnderReplicatedBlocks}} (and instances of it like {{neededReplications}}.
#* {{PendingReplicationBlocks}}
#* {{ReplicationMonitor}}
# Type inference: I'm using Java 7, which supports type inference. Since we are
already at 2.7 I think it's safe to use Java 7 features.
# bq. In the codes for above, could we have initial capacity value for the two
array lists ?
The default initial capacity is 10; I think no need to change it?
Will change other minor places in the next rev. How about {{BlockCodecInfo}} ->
{{BlockECRecoveryInfo}} and {{BlockCodecCommand}} -> {{BlockECRecoveryCommand}}?
Regarding {{testMissingStripedBlock}}: if we have 6 DNs in total and kills 1 of
them, it's uncertain how many blocks are affected. There should at least be 1
because of balanced placement algorithm. But likely < 4. I'll try to design a
more accurate test.
> Erasure coding: distribute recovery work for striped blocks to DataNode
> -----------------------------------------------------------------------
>
> Key: HDFS-7369
> URL: https://issues.apache.org/jira/browse/HDFS-7369
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Zhe Zhang
> Assignee: Zhe Zhang
> Attachments: HDFS-7369-000-part1.patch, HDFS-7369-000-part2.patch,
> HDFS-7369-001.patch, HDFS-7369-002.patch
>
>
> This JIRA updates NameNode to handle background / offline recovery of erasure
> coded blocks. It includes 2 parts:
> # Extend {{UnderReplicatedBlocks}} to recognize EC blocks and insert them to
> appropriate priority levels.
> # Update {{ReplicationMonitor}} to distinguish block codec tasks and send a
> new DataNode command.
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