Chris Harshman (1/2/2013)
I think part of the problem with SAN pools is the inherent disconnect between how network guys setup disk arrays and luns on these devices and how database people want to use them. The more I've learned about our SAN setup at my current company the less I wish I knew. Network guys seem to like making a few RAID arrays that are ginormous and then carve them out into what will be many "drives" that the OS sees. Of course with the same array serving multiple purposes for the same or multiple servers there's going to be odd contention and sub-optimal configuration. I had a network guy tell me that our RAID 10 arrays were only using 2 physical disk drives, at which I just walked away rubbing my forehead in disbelief.
I spent an absurd amount of time my first year at my current employer trying to convince the guys on the SAN/Network team that they were causing all kinds of I/O problems. "What? The SAN can handle anything, the sales guy said so...". Fortunately, we have more effective management in this department now. In the new world order of SAN admins and DBA's, I think the SAN/Network people need some theoretical education on concurrency. BTW, Brent Ozar has a lot first-rate advice on this subject.