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https://issues.apache.org/jira/browse/HDFS-10301?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15524968#comment-15524968
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Arpit Agarwal commented on HDFS-10301:
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bq.  As all storage reports in the single RPC BR satisfy the condition that 
triggers removal of the lease, all storage reports after the first storage 
report will be ignored without the change.
Isn't that because the patch also removes the lastStorageInRpc check? If that 
check was not removed then the workaround wouldn't be necessary.

bq. When BRs are split into multiple RPCS: Say 2 BRs from the same DN are 
processed at the same time.
We should make a more resilient fix that doesn't require the lease ID 
workaround. In the interests of making forward progress, can we just remove the 
zombie processing for now and fix the other issues separately?

> BlockReport retransmissions may lead to storages falsely being declared 
> zombie if storage report processing happens out of order
> --------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: HDFS-10301
>                 URL: https://issues.apache.org/jira/browse/HDFS-10301
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode
>    Affects Versions: 2.6.1
>            Reporter: Konstantin Shvachko
>            Assignee: Vinitha Reddy Gankidi
>            Priority: Critical
>         Attachments: HDFS-10301.002.patch, HDFS-10301.003.patch, 
> HDFS-10301.004.patch, HDFS-10301.005.patch, HDFS-10301.006.patch, 
> HDFS-10301.007.patch, HDFS-10301.008.patch, HDFS-10301.009.patch, 
> HDFS-10301.01.patch, HDFS-10301.010.patch, HDFS-10301.011.patch, 
> HDFS-10301.012.patch, HDFS-10301.013.patch, HDFS-10301.014.patch, 
> HDFS-10301.branch-2.7.patch, HDFS-10301.branch-2.patch, 
> HDFS-10301.sample.patch, zombieStorageLogs.rtf
>
>
> When NameNode is busy a DataNode can timeout sending a block report. Then it 
> sends the block report again. Then NameNode while process these two reports 
> at the same time can interleave processing storages from different reports. 
> This screws up the blockReportId field, which makes NameNode think that some 
> storages are zombie. Replicas from zombie storages are immediately removed, 
> causing missing blocks.



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