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https://issues.apache.org/jira/browse/HDFS-1172?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14790913#comment-14790913
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Jing Zhao commented on HDFS-1172:
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Thanks for keeping working on the issue, [~walter.k.su] and [~iwasakims]. Looks
like the rebased patches only put not-yet-received replicas into the pending
replication queue, but {{BlockManager#checkReplication}} has not been updated
accordingly. Thus the missing part is: we decide whether to add the block to
under replicated queue or pending replica queue based on its finalized replica
# and unfinalized replica #. Please see Hairong's
[comment|https://issues.apache.org/jira/browse/HDFS-1172?focusedCommentId=13013749&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13013749].
> Blocks in newly completed files are considered under-replicated too quickly
> ---------------------------------------------------------------------------
>
> Key: HDFS-1172
> URL: https://issues.apache.org/jira/browse/HDFS-1172
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 0.21.0
> Reporter: Todd Lipcon
> Attachments: HDFS-1172-150907.patch, HDFS-1172.008.patch,
> HDFS-1172.patch, hdfs-1172.txt, hdfs-1172.txt, replicateBlocksFUC.patch,
> replicateBlocksFUC1.patch, replicateBlocksFUC1.patch
>
>
> I've seen this for a long time, and imagine it's a known issue, but couldn't
> find an existing JIRA. It often happens that we see the NN schedule
> replication on the last block of files very quickly after they're completed,
> before the other DNs in the pipeline have a chance to report the new block.
> This results in a lot of extra replication work on the cluster, as we
> replicate the block and then end up with multiple excess replicas which are
> very quickly deleted.
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