They are the same. If you are referring to 0+1 vs. 10, there is a fairly major difference. Raid 10 is a stripe set with no parity (RAID 0) which is not normally redundant. But in this case, each drive in the stripe set has a mirror. So a RAID 0 of three drives becomes RAID 0+1 when you mirror each one of those three drives to another drive. So essentially, you use 50% of your drive space for Fault Tolerance. RAID 0+1 is the opposite... it is a mirror of two stripe sets. So you start with two RAID 0 stripe sets of the same size, and then you mirror from one set to the other. You end up with two identical "sets" of data, but probably no two identical "drives" of data. You also sacrifice 50% of the drive space to FT. RAID 10 is far more fault tolerant than 0+1 though... in 0+1, if a single drive fails, the entire drive set fails, hence one image of the Mirror fails, and there goes your FT... You are left with a single, non-FT RAID 0 array. a RAID 10 array can handle up to half of the drives failing, as long as they are the "correct" half. For each "drive" in the overall RAID 0 stripe set you have two copies, so you can afford to lose one of each mirror pair, and the RAID 0 set will still function. Boiled down, RAID 10 is a stripe set made up of mirrors, RAID 0+1 is a mirror set made up of stripes. Confusing as hell, Glenn Sullivan, MCSE+I MCDBA David Clark Company Inc. ________________________________ From: windows2000-bounce@xxxxxxxxxxxxx [mailto:windows2000-bounce@xxxxxxxxxxxxx] On Behalf Of Beckett, William (Bill) Posted At: Tuesday, October 03, 2006 11:20 AM Posted To: Windows 2000 Conversation: Hardware Raid question Subject: [windows2000] Hardware Raid question Can one of you hardware/RAID gurus explain the suttle differences between Raid 1+0 and Raid 10?