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From lwl <lwl.ro...@gmail.com>
Subject Re: [***SPAM*** ] Re: [***SPAM*** ] Re: [***SPAM*** ] Re: writing speed test
Date Wed, 02 Jun 2010 08:24:22 GMT
No.
But I did some capacity tests about another distributed system.
Your former test cost too much MEM, it was the bottleneck.
caches and JVM cost MEM, so I suggested to decrease them.

What is the bottleneck of your current test now?


在 2010年6月2日 下午4:13,Shuai Yuan <yuanshuai@supertool.net.cn>写道:

> Hi,
>
> I tried,
>
> 1-consistency level ZERO
>
> 2-JVM heap 4GB
>
> 3-normal Memtable cache
>
> and now I have about 30% improvment.
>
> However I want to know if you have also done w/r benchmark and what's
> the result?
>
> 在 2010-06-02三的 11:35 +0800,lwl写道:
> > and, why did you set "JVM has 8G heap"?
> > 8g, seems too big.
> >
> > 在 2010年6月2日 上午11:20,lwl <lwl.roger@gmail.com>写道:
> >         3.32 concurrent read & 128 write in storage-conf.xml, other
> >         cache
> >         enlarged as well.
> >         --------------------
> >
> >
> >         maybe you can try to decrease the size of caches.
> >
> >         在 2010年6月2日 上午11:14,Shuai Yuan
> >         <yuanshuai@supertool.net.cn>写道:
> >
> >
> >                 在 2010-06-02三的 10:37 +0800,lwl写道:
> >                 > is all the 4 servers' MEM  almost 100%?
> >
> >
> >                 Yes
> >
> >
> >                 > 在 2010年6月2日 上午10:12,Shuai Yuan
> >                 <yuanshuai@supertool.net.cn>写
> >                 > 道:
> >                 >         Thanks lwl.
> >                 >
> >                 >         Then is there anyway of tuning this, faster
> >                 flush to disk or
> >                 >         else?
> >                 >
> >                 >         Cheers,
> >                 >
> >                 >         Kevin
> >                 >
> >                 >         在 2010-06-02三的 09:57 +0800,lwl写道:
> >                 >
> >                 >         > MEM: almost 100% (16GB)
> >                 >         > -----------------
> >                 >         > maybe this is the bottleneck.
> >                 >         > writing concerns Memtable and SSTable in
> >                 memory.
> >                 >         >
> >                 >         > 在 2010年6月2日 上午9:48,Shuai Yuan
> >                 >         <yuanshuai@supertool.net.cn>写
> >                 >         > 道:
> >                 >         >         在 2010-06-01二的 15:00 -0500,
> >                 Jonathan Shook写道:
> >                 >         >         > Also, what are you meaning
> >                 specifically by 'slow'?
> >                 >         Which
> >                 >         >         measurements
> >                 >         >         > are you looking at. What are
> >                 your baseline
> >                 >         constraints for
> >                 >         >         your test
> >                 >         >         > system?
> >                 >         >         >
> >                 >         >
> >                 >         >         Actually, the problem is the
> >                 utilizaton of
> >                 >         resources(for a
> >                 >         >         single
> >                 >         >         machine):
> >                 >         >         CPU: 700% / 1600% (16 cores)
> >                 >         >         MEM: almost 100% (16GB)
> >                 >         >         Swap: almost 0%
> >                 >         >         Disk IO(write): 20~30MB / 200MB
> >                 (7.2k raid5,
> >                 >         benchmarked
> >                 >         >         previously)
> >                 >         >         NET: up to 100Mbps / 950Mbps
> >                 (1Gbps, tuned and
> >                 >         benchmarked
> >                 >         >         previously)
> >                 >         >
> >                 >         >         So the speed of generating load,
> >                 about 15M/s as
> >                 >         reported
> >                 >         >         before seems
> >                 >         >         quite slow to me. I assume the
> >                 system should get at
> >                 >         least
> >                 >         >         about 50MB/s
> >                 >         >         of Disk IO speed.
> >                 >         >
> >                 >         >         MEM? I don't think it plays a
> >                 major role in this
> >                 >         writing game.
> >                 >         >         What's
> >                 >         >         the bottleneck of the system?
> >                 >         >
> >                 >         >         P.S
> >                 >         >         about Consistency Level, I've
> >                 tried ONE/DCQUORUM and
> >                 >         found ONE
> >                 >         >         is about
> >                 >         >         10-15% faster. However that's
> >                 neither a promising
> >                 >         result.
> >                 >         >
> >                 >         >         Thanks!
> >                 >         >
> >                 >         >         Kevin
> >                 >         >
> >                 >         >         >
> >                 >         >         > 2010/6/1 史英杰
> >                 <shiyingjie1983@gmail.com>:
> >                 >         >         > > Hi, It would be better if we
> >                 know which
> >                 >         Consistency Level
> >                 >         >         did you choose,
> >                 >         >         > > and what is the schema of test
> >                 data?
> >                 >         >         > >
> >                 >         >         > > 在 2010年6月1日 下午4:48,
> >                 Shuai Yuan
> >                 >         >         <yuanshuai@supertool.net.cn>写道:
> >                 >         >         > >>
> >                 >         >         > >> Hi all,
> >                 >         >         > >>
> >                 >         >         > >> I'm testing writing speed
of
> >                 cassandra with 4
> >                 >         servers.
> >                 >         >         I'm confused by
> >                 >         >         > >> the behavior of cassandra.
> >                 >         >         > >>
> >                 >         >         > >> ---env---
> >                 >         >         > >> load-data app written in
c++,
> >                 using
> >                 >         libcassandra (w/
> >                 >         >         modified batch
> >                 >         >         > >> insert)
> >                 >         >         > >> 20 writing threads in 2
> >                 processes running on 2
> >                 >         servers
> >                 >         >         > >>
> >                 >         >         > >> ---optimization---
> >                 >         >         > >> 1.turn log level to INFO
> >                 >         >         > >> 2.JVM has 8G heap
> >                 >         >         > >> 3.32 concurrent read &
128
> >                 write in
> >                 >         storage-conf.xml,
> >                 >         >         other cache
> >                 >         >         > >> enlarged as well.
> >                 >         >         > >>
> >                 >         >         > >> ---result---
> >                 >         >         > >> 1-monitoring by
> >                 `date;nodetool -h host ring`
> >                 >         >         > >> I add all load together
and
> >                 measure the writing
> >                 >         speed by
> >                 >         >         > >> (load_difference /
> >                 time_difference), and I get
> >                 >         about
> >                 >         >         15MB/s for the
> >                 >         >         > >> whole cluster.
> >                 >         >         > >>
> >                 >         >         > >> 2-monitoring by `iostat
-m
> >                 10`
> >                 >         >         > >> I can watch the disk_io
from
> >                 the system level
> >                 >         and have
> >                 >         >         about 10MB/s -
> >                 >         >         > >> 65MB/s for a single machine.
> >                 Very big variance
> >                 >         over time.
> >                 >         >         > >>
> >                 >         >         > >> 3-monitoring by `iptraf
-g`
> >                 >         >         > >> In this way I watch the
> >                 communication between
> >                 >         servers and
> >                 >         >         get about
> >                 >         >         > >> 10MB/s for a single machine.
> >                 >         >         > >>
> >                 >         >         > >> ---opinion---
> >                 >         >         > >> So, have you checked the
> >                 writing speed of
> >                 >         cassandra? I
> >                 >         >         feel it's quite
> >                 >         >         > >> slow currently.
> >                 >         >         > >>
> >                 >         >         > >> Could anyone confirm this
is
> >                 the normal writing
> >                 >         speed of
> >                 >         >         cassandra, or
> >                 >         >         > >> please provide someway of
> >                 improving it?
> >                 >         >         > >> --
> >                 >         >         > >> Kevin Yuan
> >                 >         >         > >> www.yuan-shuai.info
> >                 >         >         > >>
> >                 >         >         > >>
> >                 >         >         > >
> >                 >         >         > >
> >                 >         >         >
> >                 >         >
> >                 >         >
> >                 >         >         --
> >                 >         >
> >                 >         >         Kevin Yuan
> >                 >         >         www.yuan-shuai.info
> >                 >         >
> >                 >         >
> >                 >         >
> >                 >         >
> >                 >         >
> >                 >
> >                 >
> >                 >         --
> >                 >         Shuai Yuan 袁帅
> >                 >         Supertool Corp. 北京学之途网络科技有限公司
> >                 >
> >                 >         www.yuan-shuai.info
> >                 >
> >                 >
> >                 >
> >
> >
> >                 --
> >
> >                 Shuai Yuan 袁帅
> >                 Supertool Corp. 北京学之途网络科技有限公司
> >                 www.yuan-shuai.info
> >
> >
> >
> >
> >
> >
> >
>
> --
> Shuai Yuan 袁帅
> Supertool Corp. 北京学之途网络科技有限公司
> www.yuan-shuai.info
>
>
>

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