Performance Issue: Keeping rows in memory

2014-10-22 Thread Thomas Whiteway
Hi, I'm working on an application using a Cassandra (2.1.0) cluster where - our entire dataset is around 22GB - each node has 48GB of memory but only a single (mechanical) hard disk - in normal operation we have a low level of writes and no reads - very

Re: Performance Issue: Keeping rows in memory

2014-10-22 Thread DuyHai Doan
If you're using 2.1.0 the row cache has been redesigned. How did you configure it ? There is some new parameters to specify how many CQL rows you want to keep in the cache: http://www.datastax.com/dev/blog/row-caching-in-cassandra-2-1 On Wed, Oct 22, 2014 at 1:34 PM, Thomas Whiteway

Re: Performance Issue: Keeping rows in memory

2014-10-22 Thread Jonathan Haddad
First, did you run a query trace? I recommend Al Tobey's pcstat util to determine if your files are in the buffer cache: https://github.com/tobert/pcstat On Wed, Oct 22, 2014 at 4:34 AM, Thomas Whiteway thomas.white...@metaswitch.com wrote: Hi, I’m working on an application using a

RE: Performance Issue: Keeping rows in memory

2014-10-22 Thread Thomas Whiteway
: Performance Issue: Keeping rows in memory If you're using 2.1.0 the row cache has been redesigned. How did you configure it ? There is some new parameters to specify how many CQL rows you want to keep in the cache: http://www.datastax.com/dev/blog/row-caching-in-cassandra-2-1 On Wed, Oct 22, 2014 at 1

Re: Performance Issue: Keeping rows in memory

2014-10-22 Thread Robert Coli
On Wed, Oct 22, 2014 at 4:34 AM, Thomas Whiteway thomas.white...@metaswitch.com wrote: I’m working on an application using a Cassandra (2.1.0) cluster where - our entire dataset is around 22GB - each node has 48GB of memory but only a single (mechanical) hard disk -