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From: jw schultz <jw@pegasys.ws>
To: linux-kernel@vger.kernel.org
Subject: Re: RAID-6 support in kernel?
Date: Tue, 4 Jun 2002 19:51:13 -0700	[thread overview]
Message-ID: <20020604195113.G7742@pegasys.ws> (raw)
In-Reply-To: <Pine.LNX.4.33.0206031020290.30424-100000@mail.pronto.tv> <Pine.GSO.4.21.0206030213510.23709-100000@gecko.roadtoad.net> <20020603113128.C13204@ucw.cz>

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

  parent reply	other threads:[~2002-06-05  2:51 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-06-02 23:01 RAID-6 support in kernel? Roy Sigurd Karlsbakk
2002-06-02 23:01 ` Roy Sigurd Karlsbakk
2002-06-03  0:33 ` Derek Vadala
2002-06-03  8:24   ` Roy Sigurd Karlsbakk
2002-06-03  8:24     ` Roy Sigurd Karlsbakk
2002-06-03  9:25     ` Derek Vadala
2002-06-03  9:31       ` Vojtech Pavlik
2002-06-03 14:52         ` Kasper Dupont
2002-06-03 14:52           ` Kasper Dupont
2002-06-03 14:55           ` Vojtech Pavlik
2002-06-04 12:49           ` Roy Sigurd Karlsbakk
2002-06-04 15:49         ` Pavel Machek
2002-06-04 15:49         ` Pavel Machek
2002-06-04 22:27           ` Kasper Dupont
2002-06-04 22:27           ` Kasper Dupont
2002-06-05  9:36             ` Roy Sigurd Karlsbakk
2002-06-05  9:36             ` Roy Sigurd Karlsbakk
2002-06-05  9:28           ` Roy Sigurd Karlsbakk
2002-06-04 15:49         ` Pavel Machek
2002-06-05  2:51         ` jw schultz [this message]
2002-06-03 17:33       ` Gregory Leblanc
2002-06-03 19:53         ` Ross Vandegrift
2002-06-04 20:20         ` Jakob Østergaard
2002-06-05  7:57           ` Luca Berra
2002-06-05 10:53             ` Jakob Østergaard
2002-06-05 19:42               ` Luca Berra
2002-06-05 21:25                 ` background scanning for media defects (was Re: RAID-6 support in kernel?) Friedrich Lobenstock
2002-06-03  9:25     ` RAID-6 support in kernel? Derek Vadala
2002-06-04 18:50   ` Bill Davidsen
2002-06-06  1:19     ` Derek Vadala
2002-06-06  8:28       ` Kasper Dupont
2002-06-06  8:28         ` Kasper Dupont
2002-06-06 11:57         ` Helge Hafting
2002-06-04 18:50   ` Bill Davidsen
2002-06-03  7:35 ` Kasper Dupont
2002-06-03  8:28   ` Roy Sigurd Karlsbakk
2002-06-03  8:57     ` Kasper Dupont
2002-06-04 11:11       ` Allan Sandfeld
2002-06-04 12:51         ` Kasper Dupont
2002-06-04 13:58           ` Allan Sandfeld
2002-06-12  8:13             ` Kasper Dupont

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