My data is single row/key to a 500 byte column and I'm reading ALL random keys (worst case read scenario) Cache has minimal effectiveness, so the Bloom trees and indexes are getting a real work out. I'm on 8GB Ubuntu 9.10 boxes (64bit). Yea, I was griping about the performance earlier, disk is heavily used by Cassandra, so outside of going to some highend SAS stuff, not sure what to do.
From: Brandon Williams [mailto:dri...@gmail.com] Sent: Wednesday, May 05, 2010 6:47 PM To: user@cassandra.apache.org Subject: Re: performance tuning - where does the slowness come from? On Wed, May 5, 2010 at 6:36 PM, Mark Jones <mjo...@imagehawk.com<mailto:mjo...@imagehawk.com>> wrote: Have you actually managed to get 10K reads/second, or are you just estimating that you can? I've run into similar issues, but I never got reads to scale when searching for unique keys even using 40 threads, I did discover that using 80+ threads, I can actually reduce performance. I've never gotten more than 200-300 reads/second (steady state) off a 4 cluster node. I can get roughly 8K writes/second to the same cluster (although I haven't tested both simultaneously with results worth talking about). 200-300/s is pretty low, especially if you can get 8k writes/s. I would estimate that you should be getting at least a couple thousand reads/s. Here is what I've gotten from a quad core machine with two disks: http://racklabs.com/~bwilliam/cassandra/04vs05vs06.png How much data are you testing with? -Brandon
