We have two Dell MD32000i storage arrays. Our main Win 2K8 R2 file server shares a LUN on SA1 for our user files. I then robocopy the data to a LUN on SA2 each night (takes about 3 hours) as a backup, ready to cutover if we have a failure of SA1. Why couldn't I mirror the drives at the File Server level for fault tolerance? Is this a crazy idea? There may be a slight performance hit, but it will protect me gainst the failure of either SA, one of which is housed in a remote building but still on the LAN.