From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936162AbYEBVoT (ORCPT ); Fri, 2 May 2008 17:44:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758680AbYEBVoE (ORCPT ); Fri, 2 May 2008 17:44:04 -0400 Received: from pasmtpa.tele.dk ([80.160.77.114]:49092 "EHLO pasmtpA.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755337AbYEBVoC (ORCPT ); Fri, 2 May 2008 17:44:02 -0400 Subject: Re: Sharing disks amoung multiple software RAIDs From: Kasper Sandberg To: David Greaves Cc: David Rees , David Lethe , alex14641@yahoo.com, Justin Piszcz , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <481AD006.6050708@dgreaves.com> References: <1209692359.16523.2.camel@localhost> <73000.21239.qm@web50212.mail.re2.yahoo.com> <1209696179.16523.13.camel@localhost> <72dbd3150805020006p7f976a04o487389840f03b4a2@mail.gmail.com> <1209715763.7827.2.camel@localhost> <481AD006.6050708@dgreaves.com> Content-Type: text/plain; charset=ISO-8859-15 Date: Fri, 02 May 2008 23:43:50 +0200 Message-Id: <1209764630.7827.15.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.4.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2008-05-02 at 09:25 +0100, David Greaves wrote: > Kasper Sandberg wrote: > > Im not treating it as a backup, what i want, is to make sure that if 1 > > disk dies, the data is still intact and ill hopefully be able to run > > with 1 disk till the newly ordered one arrives > Probably one of the main design objectives behind RAID/md Exactly, but once people start saying: "Look how many problems people post to the thread on a weekly basis where people lose their data when md rebuilds go bad with non-shared disks" i begin to worry.. > > > So my question remains.. Is md raid1 not suited for this need? would it > > be safer to run in non-raid1 mode and daily(maybe hourly) rsync > > everything over to the second disk? > > md is 100% guaranteed perfect or your money back... > rsync is 100% guaranteed perfect or your money back... > your backups are 100% guaranteed perfect or your money back... > your hard drives are 100% guaranteed perfect or your money back... > your CPU and RAM are 100% guaranteed perfect or your money back... > your CPU and PSU fans are 100% guaranteed perfect or your money back... > > Clearly if you want to panic over reliability you have lots of choices :) I do not wish to panic, i merely wished to know if linux MD is believed to work in most cases, or believed to do all sorts of weird stuff when resyncing :) > > David > PS, FWIW md has saved my data* countless times over the past 'n' years in > exactly the scenario you describe. It has also been useful to people i know, i just wished to be sure :) and as Keld Jørn Simonsen and Helge Hafting's comments seems to confirm, linux md IS nice and stable :) and as said, what im looking for isnt an in-box backup solution, merely safety in case one disk burns :) > > *(or more accurately has saved me from having to restore my data)