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From 史英杰 <shiyingjie1...@gmail.com>
Subject Re: writing speed test
Date Tue, 01 Jun 2010 12:15:17 GMT
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
>
>
>

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