RAID 1+0 with only 3 HDDs?

[Turbonium]

I thought this was possible? Say you have the following:

2x100GB RAID 0
1x200GB mirror of RAID 0 array

If a 100GB drive dies, the RAID 0 array breaks, but then it defaults to the 200GB drive to access data or write. If the 200GB drive dies, it just means you've lost redundancy that way, and just replace the drive, and it rebuilds from the striped drives.

How does it not work that way? Why do you need 4 drives in strict RAID speak?

Or am I just talking about RAID 5?

 

[Daedalus685]

Raid 1+0 is a striping of mirrors, and is at minimum 2*2. You are applying a raid 0 to a pair of raid 1s.

What you're likely wanting is Raid 0+1, a mirror of a stripe which can be 3 disks. I don't believe any of the intel chipsets support 0+1 though, you'd need a more fully featured controller to do it. (they only support 0, 1, 5, 1+0).

I can't see why Raid 5 wouldn't do what you want though. However you'd need identical disks.

 

[Nothinman]

Generally it doesn't work like that and requires 4 drives, however you should be able to manually do that with software RAID. Well, that depends on the implementation of software RAID. I believe Linux software RAID is flexible enough to let you do that, but I would be surprised if other implementations, like the one in Windows, would let you.