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https://issues.apache.org/jira/browse/HBASE-10528?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14266806#comment-14266806
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Hudson commented on HBASE-10528:
--------------------------------

FAILURE: Integrated in HBase-1.1 #63 (See 
[https://builds.apache.org/job/HBase-1.1/63/])
HBASE-10528 DefaultBalancer selects plans to move regions onto draining nodes 
(Churro Morales) (tedyu: rev c5b0a1b8a0a7db7c48473b8f3867146abfe076c1)
* 
hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestRegionStates.java
* hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStates.java


> DefaultBalancer selects plans to move regions onto draining nodes
> -----------------------------------------------------------------
>
>                 Key: HBASE-10528
>                 URL: https://issues.apache.org/jira/browse/HBASE-10528
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 0.94.5
>            Reporter: churro morales
>            Assignee: churro morales
>             Fix For: 2.0.0, 0.98.10, 1.1.0, 0.94.27
>
>         Attachments: HBASE-10528-0.94.patch, HBASE-10528-0.98.patch, 
> HBASE-10528.patch, HBASE-10528.v2.patch
>
>
> We have quite a large cluster > 100k regions, and we needed to isolate a 
> region was very hot until we could push a patch.  We put this region on its 
> own regionserver and set it in the draining state.  The default balancer was 
> selecting regions to move to this cluster for its region plans.  
> It just so happened for other tables, the default load balancer was creating 
> plans for the draining servers, even though they were not available to move 
> regions to.  Thus we were closing regions, then attempting to move them to 
> the draining server then finding out its draining. 
> We had to disable the balancer to resolve this issue.
> There are some approaches we can take here.
> 1. Exclude draining servers altogether, don't even pass those into the load 
> balancer from HMaster.
> 2. We could exclude draining servers from ceiling and floor calculations 
> where we could potentially skip load balancing because those draining servers 
> wont be represented when deciding whether to balance.
> 3. Along with #2 when assigning regions, we would skip plans to assign 
> regions to those draining servers.
> I am in favor of #1 which is simply removes servers as candidates for 
> balancing if they are in the draining state.
> But I would love to hear what everyone else thinks.



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