We are currently looking into a SAN to store our virtual machines on. The SAN will also be used for file storage and data backup. My question is concerning the type of disks that would be needed for the environment. I want to put together a SAN that is both budget friendly as well as performance oriented if that is possible. Do the vm's run on the ESX server or do they run off the disks they are stored on? I guess what I am trying to ask is if I stored teh vm's on slower SATA disks would it be noticeable to the suer accessing that vm? The vm's currently reside on a Dell server where ESXi is installed. My plan would be to migrate teh vm's to the SAN and cluster the 3 ESXi servers and access vm's from SAN. Also, what RAID is preffered for both vm storage and file storage? File storage is mostly reading.