Thanks Peter.
I believe...I found the root cause. Switch that we used was bad.
Now on a 4 node cluster ( Each Node has 1 CPU  - Quad Core and 16 GB of RAM),
I was able to get around 11,000 writes and 10,050 reads per second simultaneously (CPU usage is around 45% on all nodes. Disk queue size is in the neighbourhood of 10)
Is this inline with what you usually see with Cassandra?
----- Original Message -----
From: Peter Schuller
Sent: Friday, April 29, 2011 12:21 PM
Subject: Re: Performance tests using stress testing tool

> Thanks Peter. I am using java version of the stress testing tool from the
> contrib folder. Is there any issue that should be aware of? Do you recommend
> using pystress?

I just saw Brandon file this:

Maybe that's it.

/ Peter Schuller