From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263214AbTJKDt5 (ORCPT ); Fri, 10 Oct 2003 23:49:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263254AbTJKDt5 (ORCPT ); Fri, 10 Oct 2003 23:49:57 -0400 Received: from vladimir.pegasys.ws ([64.220.160.58]:34064 "EHLO vladimir.pegasys.ws") by vger.kernel.org with ESMTP id S263214AbTJKDty (ORCPT ); Fri, 10 Oct 2003 23:49:54 -0400 Date: Fri, 10 Oct 2003 20:49:51 -0700 From: jw schultz To: linux-kernel@vger.kernel.org Subject: Re: 2.7 thoughts Message-ID: <20031011034951.GE4716@pegasys.ws> Mail-Followup-To: jw schultz , linux-kernel@vger.kernel.org References: <20031009165723.43ae9cb5.skraw@ithnet.com> <3F864F82.4050509@longlandclan.hopto.org> <200310100830.03216.kevcorry@us.ibm.com> <20031010182918.GF1084@marowsky-bree.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20031010182918.GF1084@marowsky-bree.de> User-Agent: Mutt/1.3.27i X-Message-Flag: The contents of this message may cause sleeplessness, irritability, loss of appetite, anxiety, depression, or other psychological disorders. Consult your doctor if these symptoms persist. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 10, 2003 at 08:29:18PM +0200, Lars Marowsky-Bree wrote: > On 2003-10-10T08:30:03, > Kevin Corry said: > > > On Friday 10 October 2003 01:19, Stuart Longland wrote: > > > - Software RAID 0+1 perhaps? > > Because RAID 0+1 is a rather bad idea. You want RAID 1+0. Make up the > fault matrix and simulate what happens if drives fail. > > We can do both though, as Kevin pointed out. So if you want to shot > yourself in the foot, in the best Unix tradition, we allow you to ;) I concur with one caviat. 0+1 has the advantage of extendability that doesn't exist with 1+0. 1. break mirror downing side A 2. break stripe A 3. build new stripe A with added disk(s) 4. copying stripe B to stripe A 5. break stripe B 6. build new stripe B with added disk(s) 7. build mirror (A->B) It may even be possible to do this live. So if gradual extendability is more important than surviving multiple failures 0+1 has the advantage. Normally i prefer the reliability or to do striping at the logical volume level. -- ________________________________________________________________ J.W. Schultz Pegasystems Technologies email address: jw@pegasys.ws Remember Cernan and Schmitt