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https://issues.apache.org/jira/browse/HDFS-8827?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14654834#comment-14654834
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Walter Su commented on HDFS-8827:
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DFSTestUtil.createStripedFile(..) is used earlier because
DFSStripedOutputStream is not finished yet.
Now you can just use DFSTestUtil.createFile(..). But after that you have to
figure out the empty DNs from LocatedBlock. So you can inject the redundant
blocks to those empty DNs.
> Erasure Coding: When namenode processes over replicated striped block, NPE
> will be occur in ReplicationMonitor
> --------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-8827
> URL: https://issues.apache.org/jira/browse/HDFS-8827
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Takuya Fukudome
> Assignee: Takuya Fukudome
> Attachments: HDFS-8827.1.patch, processing-over-replica-npe.log
>
>
> In our test cluster, when namenode processed over replicated striped blocks,
> null pointer exception(NPE) occurred. This happened under below situation: 1)
> some datanodes shutdown. 2) namenode recovers block group which lost internal
> blocks. 3) restart the stopped datanodes. 4) namenode processes over
> replicated striped blocks. 5) NPE occurs
> I think BlockPlacementPolicyDefault#chooseReplicaToDelete will return null in
> this situation which causes this NPE problem.
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