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https://issues.apache.org/jira/browse/HDFS-630?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Cosmin Lehene updated HDFS-630:
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Affects Version/s: (was: 0.20.1)
Status: Patch Available (was: Open)
Adapted for 0.21 branch.
Added excludedNodes back to BlockPlacementPolicy.
Adapted to use HashMap<Node, Node> instead of List<Node> since
BlockPlacementPolicyDefault was changed to use HashMap. However I'm not sure if
it's supposed to be a HashMap...
Luckily, Dhruba didn't removed the code that dealt with excludedNodes from
BlockPlacementPolicyDefault so I only had to wire up the methods.
I also added a "unit" test - it's practically a functional test that spins up a
DFSMiniCluster with 3 DataNodes and kills one before creating the file.
> In DFSOutputStream.nextBlockOutputStream(), the client can exclude specific
> datanodes when locating the next block.
> -------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-630
> URL: https://issues.apache.org/jira/browse/HDFS-630
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: hdfs client
> Affects Versions: 0.21.0
> Reporter: Ruyue Ma
> Assignee: Ruyue Ma
> Priority: Minor
> Fix For: 0.21.0
>
> Attachments: HDFS-630.patch
>
>
> created from hdfs-200.
> If during a write, the dfsclient sees that a block replica location for a
> newly allocated block is not-connectable, it re-requests the NN to get a
> fresh set of replica locations of the block. It tries this
> dfs.client.block.write.retries times (default 3), sleeping 6 seconds between
> each retry ( see DFSClient.nextBlockOutputStream).
> This setting works well when you have a reasonable size cluster; if u have
> few datanodes in the cluster, every retry maybe pick the dead-datanode and
> the above logic bails out.
> Our solution: when getting block location from namenode, we give nn the
> excluded datanodes. The list of dead datanodes is only for one block
> allocation.
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