Re: RAID-6 support in kernel?

jw schultz (jw@pegasys.ws)
Tue, 4 Jun 2002 19:51:13 -0700

On Mon, Jun 03, 2002 at 11:31:28AM +0200, Vojtech Pavlik wrote:
> On Mon, Jun 03, 2002 at 02:25:22AM -0700, Derek Vadala wrote:
>
> He was thinking "mirror", not "stripe". Mirror of 2 RAID-5 arrays (would
> be probably called RAID-15 (when there is a RAID-10 for mirrored stripe
> arrays)), can withstand any two disks failing anytime. Even more for
> certain combinations. But it is terribly inefficient.

All the authoritative literature says that
RAID-10 is striped mirrors (survive ~1/n 2 disk failures.)
RAID-0+1 is mirrored stripes (survive ~1/2 2 disk failures.)

What he is describing would be RAID-5+1, mirrored RAID-5s.
RAID-15 would be a RAID-5 of mirrors.
Both of these could survive any 3 disk failures.

-- 
________________________________________________________________
	J.W. Schultz            Pegasystems Technologies
	email address:		jw@pegasys.ws


		Remember Cernan and Schmitt
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/