Subject: Linux Settings for G98 performance

From: Stephen Garrison <[email-masked]>
Date: Tue, 01 Apr 2003 10:46:10 -0500

I am not sure if anyone on this list will have any recommendations, but 
I have not heard anything from the LUG so far. So, I figured it was 
worth a shot.

I am trying to eek out as much performance as I can from machines in a 
cluster for which I am responsible and wondering if anyone here has some 
recomendations on the Linux file system and swap parameters.

Each machine is a Dual AMD MP1800 with 1.5GB of memory. There is a maximum
of 2 jobs running on each machine and many of the jobs that we run can 
use 400MB+ of memory and write 15GB of scratch files to disk. When two 
heavy jobs (CCSD(T) with large memory (but combined less than 1.5GB) and 
disk usage) are running on the same machine, performance is severely 
degraded. The load on the machines appears to spike when the jobs are 
writing scratch files to the disk.

I have seen values for the parameters to tune bdflush, buffermem, and 
kswapd, but generally only for use with Oracle. I was wondering if 
anyone here had done some tuning of these parameters and/or had any 
recommendations given our situation and setup.

I realize that the best thing will be to try out various values and get 
real world numbers, but I am looking for some direction or indication of 
what I might look at first and parameter values likely to improve 
performance. Thanks for any help you can provide.