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https://issues.apache.org/jira/browse/HBASE-1019?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrew Purtell updated HBASE-1019:
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Attachment: 1019.patch
There are two parts of the attached patch, that don't necessarily have to go in
together.
1) Regionservers will relinquish meta regions by closing them proactively if
under heap stress. Heap stress is defined as available heap falling below a
minimum threshold (20MB) even after forced GC. Hysteresis is applied via a two
minute waiting time between assignment of a region and a close of it, so even
if all regionservers are under heap stress a meta region will find a home.
2) Some changes to HServerLoad make load comparisons heap aware.
- If the number of regions is less, but heap use is greater, consider the load
higher. Otherwise, lower.
- If the number of regions is greater, the load is always greater.
- If the number of regions is equal, the load difference is determined by heap
usage.
I'm not advocating this patch go in right away. There are some questions:
Item #1 above will close ROOT. Will the master be able to recover from this?
(It will also close META regions, but I think this is ok.)
Item #2 above will change the behavior of the balancer and should be tested on
a cluster first.
> Master should reassign regions away from regionservers under heap stress
> ------------------------------------------------------------------------
>
> Key: HBASE-1019
> URL: https://issues.apache.org/jira/browse/HBASE-1019
> Project: Hadoop HBase
> Issue Type: Improvement
> Components: master, regionserver
> Reporter: Andrew Purtell
> Fix For: 0.19.0
>
> Attachments: 1019.patch
>
>
> Once the changes for HBASE-1018 go in, the master should reassign regions
> away from regionservers that indicate heap stress to those that do not.
> Reassignment activity must be smart enough not to overload remaining
> regionservers.
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