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From Ryan Rawson <ryano...@gmail.com>
Subject Re: how many regions a regionserver can support
Date Sat, 28 Aug 2010 20:05:55 GMT
The only downside to having so many regions on a regionserver is
opening and reassigning them is not as fast as you'd like.

In the future with increased parallelism and other things we will be
able to speed it up.



On Fri, Aug 27, 2010 at 10:55 AM, Jonathan Gray <jgray@facebook.com> wrote:
> There is no fixed limit, it has much more to do with the read/write load than the actual
dataset size.
>
> HBase is usually fine having very densely packed RegionServers, if much of the data is
rarely accessed.  If you have extremely high numbers of regions per server and you are writing
to all of these regions, or even reading from all of them, you could have issues.  Though
storage capacity needs to be considered, capacity planning often has much more to do with
how much memory you need to support the read/write load you expect.  Reads mostly from a
performance POV but for writes, there are some important considerations related to the number
of regions per server (and thus data density and determining your max region size).
>
> In any case, you should probably increase your max size to 1GB or so and can go higher
if necessary.
>
> JG
>
>> -----Original Message-----
>> From: Jinsong Hu [mailto:jinsong_hu@hotmail.com]
>> Sent: Friday, August 27, 2010 10:03 AM
>> To: user@hbase.apache.org
>> Subject: how many regions a regionserver can support
>>
>> Hi, There :
>>    Does anybody know how many region a regionserver can support ? I
>> have
>> regionservers with 8G ram and 1.5T disk and 4 core CPU.
>> I searched http://www.facebook.com/note.php?note_id=142473677002 and
>> they
>> say google target is 100 regions of 200M for each
>> regionserver.
>>   In my case, I have 2700 regions spread to 6 regionservers. each
>> region is
>> set to default size of 256M . and it seems it is still running fine. I
>> am
>> running CDH3.  I just wonder what is the upper limit so that I can do
>> capacity planning. Does anybody know this ?
>>
>> Jimmy.
>
>

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