Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 4 Jun 2002 07:11:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 4 Jun 2002 07:11:07 -0400 Received: from [213.237.118.153] ([213.237.118.153]:45696 "EHLO Princess") by vger.kernel.org with ESMTP id ; Tue, 4 Jun 2002 07:11:06 -0400 From: Allan Sandfeld To: Linux-Kernel Subject: Re: RAID-6 support in kernel? Date: Tue, 4 Jun 2002 13:11:03 +0200 User-Agent: KMail/1.4.5 In-Reply-To: <3CFB2F92.34D174C3@daimi.au.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline Message-Id: <200206041311.03631.linux@sneulv.dk> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Monday 03 June 2002 10:57, Kasper Dupont wrote: > Roy Sigurd Karlsbakk wrote: > > > > RAID-6 layout: http://www.acnc.com/04_01_06.html > > > > > > If it is supposed to survive two arbitrary disk failures something is > > > wrong with that figure. They store 12 logical sectors in 20 physical > > > sectors across 4 drives. With two lost disks there are 10 physical > > > sectors left from which we want to reconstruct 12 logical sectors. > > > That is impossible. > > > > Might be the diagram is wrong. > > Could be the case, so until I find another description I will > still not know how RAID-6 works. > It's not just the diagram, the theory is wrong. You need to use at least log2 n+1 disks for partition if you want to handle any two lost/borked disks. (16 disks would give 11x diskspace). - 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/