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https://issues.apache.org/jira/browse/HBASE-6721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13483550#comment-13483550
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Elliott Clark commented on HBASE-6721:
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Just some initial thoughts:
* I couldn't seem to get it to compile for me on 0.94
* There seem to be a bunch of formatting changes that aren't needed.
* Passing in the preferred server into the load balancer on randomAssignment is
messy. If we know the preferred server why call this function at all ?
* The balancer is a public interface and we can't make changes to it in a minor
release. And this patch won't apply to trunk.
* With this many interfaces and classes it might make sense to move them into a
namespace.
* Why is GroupAdminClient in the master namespace and not in the client
namespace.
* Why a co-processor and not build it in ?
** Security was done that was because it can be added or removed. As the patch
is that's not really possible
** This makes a lot of changes in core code for something that is a
co-processor.
* Don't create a DefaultLoadBalancer in GroupBasedLoadBalancer. The balancer
was made pluggable and that feature shouldn't go away.
* Why return ArrayListMultimap from groupRegions in GroupBasedLoadBalancer? Why
not the base class
* HTableDescriptor seems like the correct location for info about the table if
you don't want to put that data into meta.
* putting things into the filesystem seems like the wrong way to do it. There
are just so many different moving parts with getting things from hdfs with
caching and cache invalidation, and edge cases on failure.
* There's a lot of logic about balancing bleeding into the AssignmentManager.
Right now assignment manager is already too complex. I would much prefer a
solution that had everything in the balancer.
> RegionServer Group based Assignment
> -----------------------------------
>
> Key: HBASE-6721
> URL: https://issues.apache.org/jira/browse/HBASE-6721
> Project: HBase
> Issue Type: New Feature
> Reporter: Francis Liu
> Assignee: Vandana Ayyalasomayajula
> Fix For: 0.96.0
>
> Attachments: HBASE-6721_94.patch, HBASE-6721_94.patch,
> HBASE-6721-DesigDoc.pdf
>
>
> In multi-tenant deployments of HBase, it is likely that a RegionServer will
> be serving out regions from a number of different tables owned by various
> client applications. Being able to group a subset of running RegionServers
> and assign specific tables to it, provides a client application a level of
> isolation and resource allocation.
> The proposal essentially is to have an AssignmentManager which is aware of
> RegionServer groups and assigns tables to region servers based on groupings.
> Load balancing will occur on a per group basis as well.
> This is essentially a simplification of the approach taken in HBASE-4120. See
> attached document.
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