On 09/16/2013 02:49 AM, Grant wrote: >> >> If it's Type 2, then four drives with a spare is equally tolerant. >> Slightly better, even, if you take into account the reduced probability >> of 2/5 of the drives failing compared to 2/6. > > Thank you very much for this info. I had no idea. Is there another > label for these RAID types besides "Type 1" and "Type 2"? I can't > find reference to those designations via Google.
Nothing standard. RAID 10 pretty intuitively comes from RAID 1+0, which can be read aloud to figure out what it means: "RAID 1, plus RAID 0," i.e. you do RAID 1, then stripe (RAID 0) the result. The trick is that RAID 1 can refer to either mirroring (2-way) or multi-mirroring (3-way) [1]. In the end, the designation is the same: RAID 1. So if you stripe either of them, you wind up with RAID 10. In other words, "RAID 10" doesn't tell you which one you're going to get. If I ever find a controller that will do multi-mirroring + RAID 0, I'll let you know what they call it =) [1] http://www.snia.org/tech_activities/standards/curr_standards/ddf
