On Fri, 2010-04-16 at 23:33 +0800, Lu Ming wrote: > 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?
I assume you're referring to http://wiki.apache.org/cassandra/FAQ#slows_down_after_lotso_inserts (which does indeed sound like what you are seeing). Following the advice there should work. Also, unless you have a very good reason for doing otherwise, I'd recommend that you use 0.6.0, the latest stable release, instead of 0.5.1. -- Eric Evans eev...@rackspace.com
