You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@hbase.apache.org by "Ted Yu (JIRA)" <ji...@apache.org> on 2011/06/01 22:24:47 UTC
[jira] [Created] (HBASE-3945) Load balancer shouldn't move the same
region in two consective balancing actions
Load balancer shouldn't move the same region in two consective balancing actions
--------------------------------------------------------------------------------
Key: HBASE-3945
URL: https://issues.apache.org/jira/browse/HBASE-3945
Project: HBase
Issue Type: Improvement
Reporter: Ted Yu
Keeping a region on the same region server would give good stability for active scanners.
We shouldn't reassign the same region in two successive calls to balanceCluster().
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (HBASE-3945) Load balancer shouldn't move the
same region in two consective balancing actions
Posted by "Ted Yu (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13044001#comment-13044001 ]
Ted Yu commented on HBASE-3945:
-------------------------------
Motivation for this JIRA was to reduce disruption to long running compactions.
Since the decision of compaction is solely made by region server, it is not easy for load balancer to know the exact timing and duration of compactions.
Shall we introduce new parameter, e.g. hbase.balancer.inert.duration, specifying the duration of keeping region on the same region server ?
> Load balancer shouldn't move the same region in two consective balancing actions
> --------------------------------------------------------------------------------
>
> Key: HBASE-3945
> URL: https://issues.apache.org/jira/browse/HBASE-3945
> Project: HBase
> Issue Type: Improvement
> Reporter: Ted Yu
>
> Keeping a region on the same region server would give good stability for active scanners.
> We shouldn't reassign the same region in two successive calls to balanceCluster().
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (HBASE-3945) Load balancer shouldn't move the
same region in two consective balancing actions
Posted by "Ted Yu (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13044027#comment-13044027 ]
Ted Yu commented on HBASE-3945:
-------------------------------
@Jonathan:
I agree with your comment.
I think we should use as few knobs as possible.
Stack suggested this approach for the problem reported by Schubert and Anty. See his comment in HBASE-3943.
> Load balancer shouldn't move the same region in two consective balancing actions
> --------------------------------------------------------------------------------
>
> Key: HBASE-3945
> URL: https://issues.apache.org/jira/browse/HBASE-3945
> Project: HBase
> Issue Type: Improvement
> Reporter: Ted Yu
>
> Keeping a region on the same region server would give good stability for active scanners.
> We shouldn't reassign the same region in two successive calls to balanceCluster().
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (HBASE-3945) Load balancer shouldn't move the
same region in two consective balancing actions
Posted by "Lars Hofhansl (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13444447#comment-13444447 ]
Lars Hofhansl commented on HBASE-3945:
--------------------------------------
@Ted: Do you want to keep this open?
> Load balancer shouldn't move the same region in two consective balancing actions
> --------------------------------------------------------------------------------
>
> Key: HBASE-3945
> URL: https://issues.apache.org/jira/browse/HBASE-3945
> Project: HBase
> Issue Type: Improvement
> Reporter: Ted Yu
>
> Keeping a region on the same region server would give good stability for active scanners.
> We shouldn't reassign the same region in two successive calls to balanceCluster().
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (HBASE-3945) Load balancer shouldn't move the
same region in two consective balancing actions
Posted by "Jonathan Gray (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13044017#comment-13044017 ]
Jonathan Gray commented on HBASE-3945:
--------------------------------------
I worry about this approach of more and more knobs, especially when they don't directly address what a good/bad load balance really is.
If a region gets moved in two consecutive balancing actions, then something is wrong with the balancer in the first place. While I agree in principle that regions moving multiple times and quickly is not desirable, this will be a common outcome if the balancing algorithm isn't already taking into account metrics over time (rather than short snapshots). If we're using load but then adding all these limits/controls, it's hard to ever understand the behavior of the balancer.
> Load balancer shouldn't move the same region in two consective balancing actions
> --------------------------------------------------------------------------------
>
> Key: HBASE-3945
> URL: https://issues.apache.org/jira/browse/HBASE-3945
> Project: HBase
> Issue Type: Improvement
> Reporter: Ted Yu
>
> Keeping a region on the same region server would give good stability for active scanners.
> We shouldn't reassign the same region in two successive calls to balanceCluster().
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (HBASE-3945) Load balancer shouldn't move the
same region in two consective balancing actions
Posted by "Ted Yu (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13044046#comment-13044046 ]
Ted Yu commented on HBASE-3945:
-------------------------------
Without new parameter, we can keep any region on its region server for at least two cycles of balancing.
This somehow relates hbase.balancer.period with the expected duration of compaction(s).
Or maybe I misinterpreted Stack's comment.
> Load balancer shouldn't move the same region in two consective balancing actions
> --------------------------------------------------------------------------------
>
> Key: HBASE-3945
> URL: https://issues.apache.org/jira/browse/HBASE-3945
> Project: HBase
> Issue Type: Improvement
> Reporter: Ted Yu
>
> Keeping a region on the same region server would give good stability for active scanners.
> We shouldn't reassign the same region in two successive calls to balanceCluster().
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (HBASE-3945) Load balancer shouldn't move the
same region in two consective balancing actions
Posted by "Ted Yu (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13444463#comment-13444463 ]
Ted Yu commented on HBASE-3945:
-------------------------------
Let's keep this open for a while.
At least I expect some unit test what can tell us such consecutive moves wouldn't happen.
> Load balancer shouldn't move the same region in two consective balancing actions
> --------------------------------------------------------------------------------
>
> Key: HBASE-3945
> URL: https://issues.apache.org/jira/browse/HBASE-3945
> Project: HBase
> Issue Type: Improvement
> Reporter: Ted Yu
>
> Keeping a region on the same region server would give good stability for active scanners.
> We shouldn't reassign the same region in two successive calls to balanceCluster().
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira