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HBase >> mail # user >> HBase table affinity to host(s)

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Re: HBase table affinity to host(s)
They would move over to live region servers.


On Dec 23, 2012, at 2:59 PM, Brennon Church <[EMAIL PROTECTED]> wrote:

> I'm curious.  If I disable the hbase balancer, what happens when a regionserver goes offline?  Will those regions get moved over to the remaining hosts as would normally be the case?  Or will they remain unavailable until the balancer is run manually?
> Thanks.
> --Brennon
> On 12/22/12 5:48 AM, Ted Yu wrote:
>> When region splits, the daughter regions would be placed on the same server
>> as parent region.
>> You also need to consider the case where new server crashes and its regions
>> are moved to older system.
>> In HBASE-5231 <https://issues.apache.org/jira/browse/HBASE-5231> you can
>> find a patch which does per table load balancing. You can modify that code
>> to move regions of selected table to pre-defined group of servers
>> (specified through configuration).
>> Cheers
>> On Fri, Dec 21, 2012 at 11:01 PM, Brennon Church <[EMAIL PROTECTED]> wrote:
>>> I do allow regions from other tables on the newer servers.  The issue
>>> stems from a single table that habitually causes hot regions. Not such a
>>> problem on the new servers, but when those regions hit the older systems
>>> bad things happen.  I think the proper long-term solution is to change the
>>> code writing to the table, but that's not something that can be done right
>>> now, so I'm looking for the second best option.
>>> The HBASE-6721 option sounds perfect, if I'm reading it correctly. It
>>> doesn't quite fit my use case, but would solve the problem regardless.
>>> If I understand the balancer part correctly, a possible but ugly (IMHO)
>>> option would be to move the region(s) causing trouble over to the more
>>> powerful servers then disable automatic balancing.  Would region splits
>>> then remain on the same system as the original region?  If so, it would
>>> work around the problem but at the expense of having to manually move
>>> regions around more frequently to keep everything else balanced.
>>> Thanks.
>>> --Brennon
>>> On 12/21/12 8:48 PM, Ted Yu wrote:
>>>> Brennon:
>>>> I forgot to ask you about other tables you have. Do you allow regions of
>>>> other tables to also be assigned to this group of newer servers ?
>>>> If you do, there is possibility that the combined load on such new servers
>>>> would make response from them slow.
>>>> Cheers
>>>> On Fri, Dec 21, 2012 at 8:28 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
>>>>  What you describe is akin to HBASE-6721 region server group.
>>>>> Basically you want this table to be bound to group of region servers.
>>>>> Development for 0.94 is on-going, to my knowledge.
>>>>> Cheers
>>>>> On Fri, Dec 21, 2012 at 7:30 PM, Brennon Church <[EMAIL PROTECTED]
>>>>>> wrote:
>>>>>  0.92.0
>>>>>> I was looking at the balancer option.  I'm loathe to turn the automatic
>>>>>> balancer off and handle it manually as we have a lot of regions.  Is
>>>>>> that
>>>>>> the option you were thinking of?  Or am I missing something?
>>>>>> Thanks.
>>>>>> --Brennon
>>>>>> On 12/21/12 4:19 PM, Ted Yu wrote:
>>>>>>  Currently there is no such capability - you may need to customize load
>>>>>>> balancer.
>>>>>>> What version of HBase are you using ?
>>>>>>> Cheers
>>>>>>> On Fri, Dec 21, 2012 at 3:54 PM, Brennon Church <[EMAIL PROTECTED]>
>>>>>>> wrote:
>>>>>>>   I'm curious, is there any concept of hosting regions from a given
>>>>>>> table
>>>>>>>> only on a single host or subset of hosts in a cluster?  In our case we
>>>>>>>> have
>>>>>>>> a heavily-used table that can cause problems for the older systems in
>>>>>>>> our
>>>>>>>> cluster.  Newer systems would have less trouble, so I'd like to
>>>>>>>> restrict
>>>>>>>> regions for that one table only to those more powerful servers.
>>>>>>>> Thanks.