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From "Lu Ming" <xl...@live.com>
Subject Re: Cassandra 0.5.1 slow down after doing a lot of inserts
Date Fri, 16 Apr 2010 15:41:11 GMT
Cassandra often take >30 minutes to write about 300,000 row-mutations when 
startup and replaying commitlog!

--------------------------------------------------
From: "Lu Ming" <xluke@live.com>
Sent: Friday, April 16, 2010 11:33 PM
To: <dev@cassandra.apache.org>
Subject:  Cassandra 0.5.1 slow down after doing a lot of inserts

> Hi:
>   We have build a  storage system with 4 nodes in the cluster. We use the 
> default configuration file,
> every node have 2*E5504 CPU, 8G memory and 6*1T Sata disk.  The cluster 
> stores about 600G data.
>
>   We found that Cassandra 0.5.1 ALWAYS slow down after a lot of inserts. 
> When it happens, CPU and Disk load
> are very low. We use "tpstats" nodetools and find that more than 300,000 
> row-mutations is still pending and
> the write speed is no more than 100~200 row-mutations per second.
>  It also happens when  Cassandra starts and replays a large commitlog 
> file. So we must cost several hours to
> wait it finishs startup.
>
>  The Faq of Cassandra tells that it is caused by GC?  any other 
> explaining?
>
>
> thanks a lot. 


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