[jira] [Commented] (HBASE-15128) Disable region splits and merges in HBCK

["Matteo Bertozzi (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-15128?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15125699#comment-15125699 ] 

Matteo Bertozzi commented on HBASE-15128:
-----------------------------------------

the document in HBASE-13936 talks about dynamic configuration, but it does not show any shell or api as example. but i'm pretty sure everyone is one the same page when we say that we want something that allows to enable/disable things at runtime (e.g. hbase.snapshot.enable = false/true), or change dynamically cache, retries and other (e.g. hbase.hlog.open.timeout = N)

I don't want to block this issue, but at the moment we are just 1 no, 1 yes. 
I'd like to have something more configuration oriented, rather then a new thing that has nothing to do with our configuration system, but does exactly what we want to do with our configuration. I don't want end up in a situation where we have two configuration system running. one static and one dynamic.

Try to bring up the discussion in the dev-list or on a jira called "dynamic configuration" or something like that. I think that people looking at a jira called "disable region split and merge in hbck" does not expect a new feature as change.
If you get a couple of +1 from Andrew, Elliot and others I'm fine with that.

> Disable region splits and merges in HBCK
> ----------------------------------------
>
>                 Key: HBASE-15128
>                 URL: https://issues.apache.org/jira/browse/HBASE-15128
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Enis Soztutar
>            Assignee: Heng Chen
>             Fix For: 2.0.0, 1.3.0
>
>         Attachments: HBASE-15128.patch, HBASE-15128_v1.patch, HBASE-15128_v3.patch
>
>
> In large clusters where region splits are frequent, and HBCK runs take longer, the concurrent splits cause further problems in HBCK since HBCK assumes a static state for the region partition map. We have just seen a case where HBCK undo's a concurrently splitting region causing number of inconsistencies to go up. 
> We can have a mode in master where splits and merges are disabled like the balancer and catalog janitor switches. Master will reject the split requests if regionservers decide to split. This switch can be turned on / off by the admins and also automatically by HBCK while it is running (similar to balancer switch being disabled by HBCK). 
> HBCK  should also disable the Catalog Janitor just in case. 



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