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https://issues.apache.org/jira/browse/HDFS-1172?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Masatake Iwasaki updated HDFS-1172:
-----------------------------------
    Attachment: HDFS-1172.010.patch

bq. Also if a block's effective replica number (including pending replica 
number) is >= than its replication factor, the block should not be in 
neededReplication. 

I rethinked about this and fixed {{checkReplication}} accordingly.

I also fixed to address checkstyle warnings. Warning about file length of 
BlockManager.java is not introduced here. The failure of 
{{TestBlockManager.testBlocksAreNotUnderreplicatedInSingleRack}} seems not to 
be related to the patch and I could not reproduce it in my environment.


> 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-1172.009.patch, HDFS-1172.010.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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