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.
--Brennon
