From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 21 Sep 2001 18:44:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 21 Sep 2001 18:44:18 -0400 Received: from adsl-63-194-239-202.dsl.lsan03.pacbell.net ([63.194.239.202]:30709 "EHLO mmp-linux.matchmail.com") by vger.kernel.org with ESMTP id ; Fri, 21 Sep 2001 18:44:05 -0400 Date: Fri, 21 Sep 2001 15:44:24 -0700 From: Mike Fedyk To: "Stephen C. Tweedie" Cc: Neil Brown , linux-kernel@vger.kernel.org Subject: Re: Define conflict between ext3 and raid patches against 2.2.19 Message-ID: <20010921154424.C8738@mikef-linux.matchmail.com> Mail-Followup-To: "Stephen C. Tweedie" , Neil Brown , linux-kernel@vger.kernel.org In-Reply-To: <20010916155835.C24067@mikef-linux.matchmail.com> <15271.11056.810538.66237@notabene.cse.unsw.edu.au> <20010919133811.B22773@mikef-linux.matchmail.com> <15273.7576.395258.345452@notabene.cse.unsw.edu.au> <20010921141050.A1946@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20010921141050.A1946@redhat.com> User-Agent: Mutt/1.3.22i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 21, 2001 at 02:10:50PM +0100, Stephen C. Tweedie wrote: > Hi, > > On Thu, Sep 20, 2001 at 08:35:04AM +1000, Neil Brown wrote: > > > However when a RAID rebuild happens, every block on the array is read > > into the buffer cache (if it isn't already there) and then written > > back out again. This defeats the control that ext3 tries to maintain > > on the buffer cache. > > > > I don't know exactly what large-scale effects this might have. It > > could be simply that a crash at the wrong time could leave the > > filesystem corrupted. > > Immediately after a crash, the fs will be OK. But during the > subsequent background raid reconstruction, it can get out of sync > again. This can result in silent data loss in some cases, but it is > also likely to trigger some internal ext3 debugging which detects > out-of-order data writes, resulting in a kernel panic. > Ok, thanks guys, on ext3-users and lkml. Now I know that if I want RAID1 or RAID5 with ext3, I'm going to need 2.4... Test test test... Mike