RAID 1+0 and 0+1

[dasn]

Hi Guys,
Is there any difference between RAID 1+0 and RAID 0+1?

Thanks,
NKD

[Rob Leadbeater]

Hi,

Yes there is. RAID 1+0 consists of striped mirror sets, whilst RAID 0+1 consists of mirrored stripe sets.

For example given 6 disks with IDs 0-5, with RAID 1+0 you would mirror 0 & 1, 2 & 3, 4 & 5. Stripes would then be created across disks, 0 2 4 and 1 3 5. This means you get excellent performance and you could in theory tolerate the loss of up to 3 disks at the same.

Given the same 6 disks with RAID 0+1, you would create stripes with disks 0 2 4 and 1 3 5, and then mirror those entire stripes. In this situation a loss of a single disk would make a whole stripe fail. A concurrent failure in the other stripe and your data would be gone.

Hope this helps,

Regards,

Rob