From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760432AbYEAMv3 (ORCPT ); Thu, 1 May 2008 08:51:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756586AbYEAMvT (ORCPT ); Thu, 1 May 2008 08:51:19 -0400 Received: from mx1.ukfsn.org ([77.75.108.10]:43297 "EHLO mail.ukfsn.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753543AbYEAMvS (ORCPT ); Thu, 1 May 2008 08:51:18 -0400 Message-ID: <4819BCC4.8030504@dgreaves.com> Date: Thu, 01 May 2008 13:51:16 +0100 From: David Greaves User-Agent: Mozilla-Thunderbird 2.0.0.12 (X11/20080406) MIME-Version: 1.0 To: alex14641@yahoo.com CC: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Sharing disks amoung multiple software RAIDs References: <771640.4981.qm@web50209.mail.re2.yahoo.com> In-Reply-To: <771640.4981.qm@web50209.mail.re2.yahoo.com> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alex Davis wrote: > Is this a bad thing? I'm guessing that it is, but I want independent > confirmation before I spoke to someone I know who's doing this. > > Thanks Depends what you're trying to do. It has the potential to increase i/o contention so it's not going to be a performance win. Many systems really don't need to worry about performance. But if you have 2x250 Gb drives and 1x500 Gb drive then your data is at less risk if you partition the 500Gb into 2x250Gb and then mirror each partition with a full 250Gb disk. That would be a perfectly rational setup in many instances. Equally, md has a mechanism to share hot spares amongst multiple RAIDs - but I doubt that's what you meant. David