I've worked on a lot of systems where I've thought that, just maybe, the application was doing far too much IOPS. But how do you prove it? I've done some google searches and have seen various metrics touted, but I've never seen anything definitive. I recently (June 2012) asked this question to a MS Premier Field Engineer and I was told that anything over 100 Page Reads/sec is considered high. Our application was averaging 2000 and the maximum was about 40000.
Yeah, I'd say that is too much database I/O.
san sql server performance data architecture