Slow Disk i/o with 2 CPU's installed

[Ayman Altounji]

Hi there,

We have a DL360 with 2 P3 1000 chips & 4 gigs of RAM. We installed Red Hat 7.2 on it with 1 processor and it worked great. We installed the 2nd processor and an SMP kernel and now the disk i/o appears to be extremely slow. With either CPU in the #1 slot the machine is very fast, but when they are both installed the disk i/o slows down to about half of what it was. Also when using the either the Uni kernel or the SMP kernel and only 1 cpu the disk i/o is fine. We have also tried Red Hat 7.1 and experience the same results. We are doing chksum on a 1 gig file and using vwstat to monitor the performance aside from the fast the machine is just slow at that point.

Thanks