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https://issues.apache.org/jira/browse/HBASE-15251?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ted Yu updated HBASE-15251:
---------------------------
       Resolution: Fixed
     Hadoop Flags: Reviewed
    Fix Version/s: 2.0.0
           Status: Resolved  (was: Patch Available)

> During a cluster restart, Hmaster thinks it is a failover by mistake
> --------------------------------------------------------------------
>
>                 Key: HBASE-15251
>                 URL: https://issues.apache.org/jira/browse/HBASE-15251
>             Project: HBase
>          Issue Type: Bug
>          Components: master
>    Affects Versions: 2.0.0
>            Reporter: Clara Xiong
>            Assignee: Clara Xiong
>             Fix For: 2.0.0
>
>         Attachments: HBASE-15251-master-v1.patch, HBASE-15251-master.patch
>
>
> We often need to do cluster restart as part of release for a cluster of > 
> 1000 nodes. We have tried our best to get clean shutdown but 50% of the time, 
> hmaster still thinks it is a failover. This increases the restart time from 5 
> min to 30 min and decreases locality from 99% to 5% since we didn't use a 
> locality-aware balancer. We had a bug HBASE-14129 but the fix didn't work. 
> After adding more logging and inspecting the logs, we identified two things 
> that trigger the failover handling:
> 1.  When Hmaster.AssignmentManager detects any dead servers on service 
> manager during joinCluster(), it determines this is a failover without 
> further check. I added a check whether there is even any region assigned to 
> these servers. During a clean restart, the regions are not even assigned.
> 2. When there are some leftover empty folders for log and split directories 
> or empty wal files, it is also treated as a failover. I added a check for 
> that. Although this can be resolved by manual cleanup, it is still too 
> tedious for restarting a large cluster.
> Patch will follow shortly. The fix is tested and used in production now.



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