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https://issues.apache.org/jira/browse/HDFS-1779?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13011567#comment-13011567
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dhruba borthakur commented on HDFS-1779:
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Wait a minute, can you pl provide some more clarification? If you restart only
the NN and not the DN, then the DN still has a reference to the blocks in the
bbw directory. When the client closes the file (assuming that the client
survived the NN restart), those blocks will send a blockReceived to the NN. If
the client died, then the NN will start lease-recovery at some future point in
time and that should make these datanodes send blockReceived messages to the
NN. This sequence of events should make the blocks reappear in the NN. Are you
seeing something different?
> After NameNode restart , Clients can not read partial files even after client
> invokes Sync.
> -------------------------------------------------------------------------------------------
>
> Key: HDFS-1779
> URL: https://issues.apache.org/jira/browse/HDFS-1779
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: data-node, name-node
> Affects Versions: 0.20-append
> Environment: Linux
> Reporter: Uma Maheswara Rao G
>
> In Append HDFS-200 issue,
> If file has 10 blocks and after writing 5 blocks if client invokes sync
> method then NN will persist the blocks information in edits.
> After this if we restart the NN, All the DataNodes will reregister with NN.
> But DataNodes are not sending the blocks being written information to NN. DNs
> are sending the blocksBeingWritten information in DN startup. So, here
> NameNode can not find that the 5 persisted blocks belongs to which datanodes.
> This information can build based on block reports from DN. Otherwise we will
> loose this 5 blocks information even NN persisted that block information in
> edits.
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