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https://issues.apache.org/jira/browse/HADOOP-1349?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Marco Nicosia updated HADOOP-1349:
----------------------------------

    Priority: Blocker  (was: Major)

> Corrupted blocks get deleted but not replicated
> -----------------------------------------------
>
>                 Key: HADOOP-1349
>                 URL: https://issues.apache.org/jira/browse/HADOOP-1349
>             Project: Hadoop
>          Issue Type: Bug
>          Components: dfs
>            Reporter: Hairong Kuang
>            Assignee: Hairong Kuang
>            Priority: Blocker
>             Fix For: 0.14.0
>
>         Attachments: blockInvalidate.patch
>
>
> When I test the patch to HADOOP-1345 on a two node dfs cluster, I see that 
> dfs correctly delete the corrupted replica and successfully retry reading 
> from the other correct replica, but the block does not get replicated. The 
> block remains with only 1 replica until the next block report comes in.
> In my testcase, since the dfs cluster has only 2 datanodes, the target of 
> replication is the same as the target of block invalidation.  After poking 
> the logs, I found out that the namenode sent the replication request before 
> the block invalidation request. 
> This is because the namenode does not invalidate a block well. In 
> FSNamesystem.invalidateBlock, it first puts the invalidate request in a queue 
> and then immediately removes the replica from its state, which triggers the 
> choosing a target for the block. When requests are sent back to the target 
> datanode as a reply to a heartbeat message, the replication requests have 
> higher priority than the invalidate requests.
> This problem could be solved if a namenode removes an invalidated replica 
> from its state only after the invalidate request is sent to the datanode.

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