On May 29, 3:46*am, howa wrote:
Assume a system with 9 SATA 1TB disks, and 1 hot spare.

They are targeted to config as Raid5 or Raid6.

If one of the disk failed, which system will perform better? Raid5 and
Raid6? By how many %?

It's not a performance question - it's an availability question. If
you configure those volumes in a raid5, you will almost be guaranteed
of losing your entire array if a drive fails. The math does not work
in your favor - the odds are extremely high that under high I/O load -
during your raid5 rebuild, you will have an unrecoverable error on one
of the remaining members. At that time, your raid5 array will fail.

Don't think it won't happen to you - I've seen double-disk failures
happen on raid5 sets too often for it to be funny.

Go with raid6. If you want performance, create 4 mirror sets instead
of raid6.