I am looking at using different storage
arrays, one which will use a PSP of fixed and the other with MRU. Now
there is something in the back of my mind telling me that this is not a good
thing to do. Has anyone seen any problems with this configuration if they
have used it in the past?
I've used that setup often for a combination of Clariion/DMX arrays. I can't say for sure that there are not issues, but I never saw any personally. Are you mixing the disks inside of a VM or just on a per-VM basis? In my case it was primarily for DR purposes (SRDF/DMX for critical boxes, but not for non-critical systems).