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From Juhani Connolly <juhani_conno...@cyberagent.co.jp>
Subject Re: 0.92 and Read/writes not scaling
Date Thu, 05 Apr 2012 03:02:59 GMT
done, thanks for pointing me to that

On 04/05/2012 11:43 AM, Ted Yu wrote:
> Juhani:
> Thanks for sharing your results.
>
> Do you mind putting the summary on HBASE-5699: Run with>  1 WAL in
> HRegionServer ?
>
> On Wed, Apr 4, 2012 at 6:45 PM, Juhani Connolly<
> juhani_connolly@cyberagent.co.jp>  wrote:
>
>> another quick update on stuff:
>>
>> since moving back to hdfs 0.20.2 (with hbase still at 0.92), we found that
>> while we made significant gains in throughput, that most of our
>> regionservers IPC threads were stuck somewhere in HWal.append(out of 50, 42
>> were in append, of which 20 were in sync), limiting throughput despite
>> significant free hardware resources.
>>
>> Because the WAL writes of a single  RS all go sequentially to one HDFS
>> file, we assumed that we could improve throughput by separating writes to
>> more WAL files and more HDs. To do this we ran multiple region servers on
>> each node.
>>
>> The scaling  wasn't linear(we were in no way increasing hardware, just the
>> number of regionservers), but we are now getting significantly more
>> throughput.
>> I would personally not say that this is a great approach to have to take,
>> it would generally be better to build more smaller servers which will thus
>> not limit themselves by trying to put a lot of data per server through a
>> single WAL file.
>>
>> Of course there may be another solution to this that I'm not aware of? If
>> so I'd love to hear it.
>>


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