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https://issues.apache.org/jira/browse/HDFS-10106?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vinayakumar B deleted HDFS-10106:
---------------------------------


> CLONE - Erasure coding: fix priority level of UnderReplicatedBlocks for 
> striped block
> -------------------------------------------------------------------------------------
>
>                 Key: HDFS-10106
>                 URL: https://issues.apache.org/jira/browse/HDFS-10106
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>            Reporter: dragon
>            Assignee: Walter Su
>
> Issues 1: correctly mark corrupted blocks.
> Issues 2: distinguish highest risk priority and normal risk priority.
> {code:title=UnderReplicatedBlocks.java}
>   private int getPriority(int curReplicas,
>   ...
>     } else if (curReplicas == 1) {
>       //only on replica -risk of loss
>       // highest priority
>       return QUEUE_HIGHEST_PRIORITY;
>   ...
> {code}
> For stripe blocks, we should return QUEUE_HIGHEST_PRIORITY when curReplicas 
> == 6( Suppose 6+3 schema).
> That's important. Because
> {code:title=BlockManager.java}
> DatanodeDescriptor[] chooseSourceDatanodes(BlockInfo block,
>   ...
>      if(priority != UnderReplicatedBlocks.QUEUE_HIGHEST_PRIORITY 
>           && !node.isDecommissionInProgress() 
>           && node.getNumberOfBlocksToBeReplicated() >= maxReplicationStreams)
>       {
>         continue; // already reached replication limit
>       }
>   ...
> {code}
> It may return not enough source DNs ( maybe 5), and failed to recover.
> A busy node should not be skiped if a block has highest risk/priority. The 
> issue is the striped block doesn't have priority.



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