[jira] [Commented] (HBASE-15154) Master puts up a blockcache instance

["Anoop Sam John (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-15154?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15111914#comment-15111914 ] 

Anoop Sam John commented on HBASE-15154:
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When master host META, we dont a block cache (small size) so that META table block will get inside that?

> Master puts up a blockcache instance
> ------------------------------------
>
>                 Key: HBASE-15154
>                 URL: https://issues.apache.org/jira/browse/HBASE-15154
>             Project: HBase
>          Issue Type: Bug
>            Reporter: stack
>            Priority: Critical
>
> Master is putting up a blockcache instance. It shouldn't. This issue comes of the unification of Master and RegionServer where Master is a subclass of RegionServer. Our [~jmspaggi] found out the hard way today when he tried to bring up a cluster with a large offheap cache only the master member had been given less memory.
> Marking critical rather than blocker because there is a means of configuring your way out of this little entanglement; set hbase.bucketcache.size to zero in  the master config only.
> If you want to set direct memory for regionservers only and not on the master, you should do the following:
> Set HBASE_OFFHEAPSIZE=0G
> ... and then turn it on for RegionServers only:
> HBASE_REGIONSERVER_OPTS="HBASE_REGIONSERVER_OPTS -XX:MaxDirectMemorySize=XXXG" where XXX is size of the direct memory you want to allocate.



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