topis always high when the system is sluggish, slow. Of course, I'm usually doing a lot of disk io so it is not expected. But I did find the following site that talks about performance on the Perc controller
blockdev --getra /dev/sda
and received 256
blockdev --setra 8192 /dev/sda
Initial tests of suspending/resuming vms and copying show significant improvement.
Added the line
/sbin/blockdev --setra 8192 /dev/sda