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https://issues.apache.org/jira/browse/HDFS-10301?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15383461#comment-15383461
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Konstantin Shvachko commented on HDFS-10301:
--------------------------------------------

> adding a list of storage IDs to the block report RPC by making a 
> backwards-compatible protobuf change.

The storage ids are already there in current BR protobuf. Why would you want a 
new field for that. You will need to duplicate all storage ids in case of full 
block report, when it is not split into multiple RPCs. Seems confusing and 
inefficient to me.

> 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.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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