RHEL3 vs RHEL4
 

Hey everyone,

I'm trying to debug a problem we are having. Basically, a simulator running on RHEL3 runs extremely slow compared to RHEL4 (on the same hardware). I'm talking a 9 minute run vs 115 minute. The simluation creates a 270 MEG output file. Our default setup has the output being written to an external raid server. Here are some experiments I've tried

RHEL4 saving on external raid - 9 minutes
RHEL3 saving on external raid - 115 minutes
RHEL3 saving on local disk - 9 minutes
RHEL3 running on external raid but sending large output file to /dev/null - 9 minutes

So, it seems this is related to network speed or how we have the disk mounted. I used "dd" on a RHEL3 box to create a large file on the array and speed doesn't seem to be an issue. So something inside the simulator and how it writes is causing issues.

I'm just wondering if anyone has any thoughts on what might cause this?

Thanks