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https://issues.apache.org/jira/browse/HBASE-8517?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13665659#comment-13665659
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stack commented on HBASE-8517:
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+1 after skimming the patch and presuming you have tried it on cluster. Good
on you Elliott.
> Stochastic Loadbalancer isn't finding steady state on real clusters
> -------------------------------------------------------------------
>
> Key: HBASE-8517
> URL: https://issues.apache.org/jira/browse/HBASE-8517
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.95.0, 0.95.1
> Reporter: Elliott Clark
> Assignee: Elliott Clark
> Priority: Blocker
> Fix For: 0.95.1
>
> Attachments: HBASE-8517-0.patch, HBASE-8517-1.patch,
> HBASE-8517-2.patch, HBASE-8517-3.patch, HBASE-8517-4.patch, HBASE-8517-5.patch
>
>
> I have a cluster that runs IT tests. Last night after all tests were done I
> noticed that the balancer was thrashing regions around.
> The number of regions on each machine is not correct.
> The balancer seems to value the cost of moving a region way too little.
> {code}
> 2013-05-09 16:34:58,920 DEBUG [IPC Server handler 4 on 60000]
> org.apache.hadoop.hbase.master.balancer.StochasticLoadBalancer: Finished
> computing new load balance plan. Computation took 5367ms to try 8910
> different iterations. Found a solution that moves 37 regions; Going from a
> computed cost of 56.50254222730425 to a new cost of 11.214035466575254
> 2013-05-09 16:37:48,715 DEBUG [IPC Server handler 7 on 60000]
> org.apache.hadoop.hbase.master.balancer.StochasticLoadBalancer: Finished
> computing new load balance plan. Computation took 4735ms to try 8910
> different iterations. Found a solution that moves 38 regions; Going from a
> computed cost of 56.612624531830996 to a new cost of 11.275763861636982
> 2013-05-09 16:38:11,398 DEBUG [IPC Server handler 6 on 60000]
> org.apache.hadoop.hbase.master.balancer.StochasticLoadBalancer: Finished
> computing new load balance plan. Computation took 4502ms to try 8910
> different iterations. Found a solution that moves 39 regions; Going from a
> computed cost of 56.50048461413552 to a new cost of 11.225352339003237
> {code}
> Each of those balancer runs were triggered when there was no load on the
> cluster.
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