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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: perfomance issue
Date Fri, 25 Sep 2009 15:46:16 GMT
I still have no idea what your test looks like or what your numbers
mean.  So how can I guess if it's expected?

As a very rough rule of thumb you can expect about 1000 ops per second
on a low-end-ish system.  So if you are getting that much out of
cassandra at least you are in the right ball park.

-Jonathan

On Fri, Sep 25, 2009 at 10:41 AM, Kirill A. Korinskiy
<catap+cassandra@catap.ru> wrote:
> 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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