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From Kirill A. Korinskiy <catap+cassan...@catap.ru>
Subject Re: perfomance issue
Date Fri, 25 Sep 2009 15:41:36 GMT
At Fri, 25 Sep 2009 10:32:55 -0500,
Jonathan Ellis <jbellis@gmail.com> wrote:
> 
> Step zero in benchmarking cassandra is turning the log level to
> INFO.

sure, i'm switching off all log messages

> Step one is testing on a machine where you can put the commitlog
> directory on its own disk.

you mean a dedicated disk for commitlog?

> It's true that frequently cassandra will be slower than custom code
> writing to local disk, but that's not the interesting part of what
> cassandra does. :)
> 

sure I'm understand it. But slower ~20 times… It's really expected?

> -Jonathan
> 
> On Fri, Sep 25, 2009 at 10:23 AM, Kirill A. Korinskiy
> <catap+cassandra@catap.ru> wrote:
> > Hello.
> >
> > I'm write a small erlang benchmark: cassandra vs simple fs storage and
> > I have a results:
> >
> > fs_storage:
> > 10: 1732/228633/2873/1128 992/233261/2870/1026
> > 25: 4531/35290/6084/632 1786/35292/5969/312
> > 50: 4707/311825/13694/4644 1366/382913/14470/5823
> >
> > cassandra:
> > 10: 69014/424051/145871/28066 9553/427823/141925/29190
> > 25: 165500/536108/339736/77173 14846/710370/341819/78694
> > 50: 325790/1050753/667931/157962 9865/1033461/676317/160606
> >
> > legends:
> > parallel request: get set min/max/avg/mad
> >
> > So. Cassandra slower ~50 times.
> >
> > Ok I change cassandra setting:
> >
> >  ColumnFamily from UTF8Type to BytesType
> >  MemtableObjectCountInMillions from 0.1 to 1
> >  ConcurrentReads from 8 to 64
> >  ConcurrentWrites from 32 to 64
> >
> > And I have:
> >
> > fs_storage:
> > 10: 2164/245375/2515/474 651/247790/2746/800
> > 25: 5521/19959/5838/196 1836/20138/5943/186
> > 50: 6369/32837/11476/944 1396/32818/11449/876
> >
> > cassandra:
> > 10: 39931/279903/48463/4812 21378/278782/51477/4526
> > 25: 101911/407343/119135/9158 8794/410423/123768/9076
> > 50: 209202/429959/238179/12180 7803/442580/244402/13443
> >
> > Cassandra slower ~20 times.
> >
> > I's normal? Can I do something wrong? Maybe you have any ideas?
> >
> > --
> > wbr, Kirill
> >

-- 
wbr, Kirill

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