I'd really suggest that everyone read the entire thread before commenting. This issue is the result of the cache getting disabled on the raid controller under instances of high I/O. DELL has no known fix for this issue when it occurs. We gave them all of our logs and their only response was to have all of the firmware updated on the controller, which by the way didn't fix the problem. The only solution we have found was to use cachecade, which we are still not 100% sure actually fixes the problem, but the 1 server we configured this way hasn't had the issue since. The other option is to change to a different raid controller if possible. We have since decided to go a different route on our server builds utilizing the Intel server configurator and building the servers in-house.