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https://issues.apache.org/jira/browse/HADOOP-2065?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12535693
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Raghu Angadi commented on HADOOP-2065:
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bq. #2 above will be handled in HADOOP-2012. When it detects a corrupt block,
it just asks the Namenode to delete it (same interface is used by client when
it detects a bad block). In this case, namenode deletes the block as long as
there are more replicas. So it does not really make sure that there is at least
one good replica.
That was a premeture comment. Actually HADOOP-2012 won't do that.
> Replication policy for corrupted block
> ---------------------------------------
>
> Key: HADOOP-2065
> URL: https://issues.apache.org/jira/browse/HADOOP-2065
> Project: Hadoop
> Issue Type: Bug
> Components: dfs
> Affects Versions: 0.14.1
> Reporter: Koji Noguchi
>
> Thanks to HADOOP-1955, even if one of the replica is corrupted, the block
> should get replicated from a good replica relatively fast.
> Created this ticket to continue the discussion from
> http://issues.apache.org/jira/browse/HADOOP-1955#action_12531162.
> bq. 2. Delete corrupted source replica
> bq. 3. If all replicas are corrupt, stop replication.
> For (2), it'll be nice if the namenode can delete the corrupted block if
> there's a good replica on other nodes.
> For (3), I prefer if the namenode can still replicate the block.
> Before 0.14, if the file was corrupted, users were still able to pull the
> data and decide if they want to delete those files. (HADOOP-2063)
> In 0.14 and later, we cannot/don't replicate these blocks so they eventually
> get lost.
> To make the matters worse, if the corrupted file is accessed, all the
> corrupted replicas would be deleted except for one and stay as replication
> factor of 1 forever.
>
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