Couple of hits here, one from jonathan and some previous discussions on the user list http://www.google.co.nz/search?q=cassandra+iostat
Same here for cfhistograms http://www.google.co.nz/search?q=cassandra+cfhistograms cfhistograms includes information on the number of sstables read during recent requests. As your initial cfstats showed 236 sstables I thought it may be useful see if there was a high number of sstables been accessed per read. 70 requests per second is slow against a 6 node cluster where each node has 12 cores and 96GB of ram. Something is not right. Aaron On 12 Apr 2011, at 17:11, mcasandra wrote: > > aaron morton wrote: >> >> You'll need to provide more information, from the TP stats the read stage >> could not keep up. If the node is not CPU bound then it is probably IO >> bound. >> >> >> What sort of read? >> How many columns was it asking for ? >> How many columns do the rows have ? >> Was the test asking for different rows ? >> How many ops requests per second did it get up to? >> What do the io stats look like ? >> What does nodetool cfhistograms say ? >> > It's simple read of 1M rows with one column of avg size of 200K. Got around > 70 req per sec. > > Not sure how to intepret the iostats output with things happening async in > cassandra. Can you give little description on how to interpret it? > > I have posted output of cfstats. Does cfhistograms provide better info? > > > -- > View this message in context: > http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Timeout-during-stress-test-tp6262430p6263859.html > Sent from the cassandra-u...@incubator.apache.org mailing list archive at > Nabble.com.
