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https://issues.apache.org/jira/browse/HDFS-2202?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13071457#comment-13071457
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Hadoop QA commented on HDFS-2202:
---------------------------------
-1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12487905/HDFS-2171.patch
against trunk revision 1151238.
+1 @author. The patch does not contain any @author tags.
+1 tests included. The patch appears to include 3 new or modified tests.
+1 javadoc. The javadoc tool did not generate any warning messages.
+1 javac. The applied patch does not increase the total number of javac
compiler warnings.
+1 findbugs. The patch does not introduce any new Findbugs (version 1.3.9)
warnings.
+1 release audit. The applied patch does not increase the total number of
release audit warnings.
-1 core tests. The patch failed these core unit tests:
org.apache.hadoop.cli.TestHDFSCLI
org.apache.hadoop.hdfs.server.datanode.TestBlockRecovery
org.apache.hadoop.hdfs.server.namenode.TestBackupNode
+1 contrib tests. The patch passed contrib unit tests.
+1 system test framework. The patch passed system test framework compile.
Test results:
https://builds.apache.org/job/PreCommit-HDFS-Build/1032//testReport/
Findbugs warnings:
https://builds.apache.org/job/PreCommit-HDFS-Build/1032//artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/1032//console
This message is automatically generated.
> 0.23: Changes to balancer bandwidth should not require datanode restart.
> ------------------------------------------------------------------------
>
> Key: HDFS-2202
> URL: https://issues.apache.org/jira/browse/HDFS-2202
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: balancer, data-node
> Affects Versions: 0.20.205.0
> Reporter: Eric Payne
> Assignee: Eric Payne
> Fix For: 0.23.0
>
> Attachments: HDFS-2171.patch, HDFS-2202.patch
>
>
> Currently in order to change the value of the balancer bandwidth
> (dfs.datanode.balance.bandwidthPerSec), the datanode daemon must be restarted.
> The optimal value of the bandwidthPerSec parameter is not always (almost
> never) known at the time of cluster startup, but only once a new node is
> placed in the cluster and balancing is begun. If the balancing is taking too
> long (bandwidthPerSec is too low) or the balancing is taking up too much
> bandwidth (bandwidthPerSec is too high), the cluster must go into a
> "maintenance window" where it is unusable while all of the datanodes are
> bounced. In large clusters of thousands of nodes, this can be a real
> maintenance problem because these "mainenance windows" can take a long time
> and there may have to be several of them while the bandwidthPerSec is
> experimented with and tuned.
> A possible solution to this problem would be to add a -bandwidth parameter to
> the balancer tool. If bandwidth is supplied, pass the value to the datanodes
> via the OP_REPLACE_BLOCK and OP_COPY_BLOCK DataTransferProtocol requests.
> This would make it necessary, however, to change the DataTransferProtocol
> version.
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