[Discuss] On Btrfs raid and odd-count disks

[Shirley Márquez Dúlcey]

On Wed, Apr 10, 2013 at 11:34 AM, joe at polcari.com <joe at polcari.com> wrote:
>   How does raid 1 with an odd number of disks earn the distinction of being called RAID?If you lose one disk, you've lost data. Any disk is a single point of failure. What's the point?

Incorrect. All data is stored on two drives, and you can recover from
the loss of a single drive. It's just different from the usual
mirroring in that not all the data on a drive is stored on the SAME
other drive. If you have a three disk set, half of drive A's data is
also on drive B and the other half is on drive C. (It's similar for
drives B and C.) In a five disk set, the other copy of data from drive
A would be distributed among drives B, C, D, and E.