From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erik Mouw Subject: Re: [Ext2-devel] Re: [RFD] FS behavior (I/O failure) in kernel summit Date: Tue, 14 Jun 2005 14:51:30 +0200 Message-ID: <20050614125130.GA30812@harddisk-recovery.com> References: <1118692436.2512.157.camel@CoolQ> <42ADC99D.5000801@namesys.com> <20050613201315.GC19319@moraine.clusterfs.com> <42AE1D4A.3030504@namesys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andreas Dilger , fs , linux-fsdevel , linux-kernel , zhiming@admin.iscas.ac.cn, qufuping@ercist.iscas.ac.cn, madsys@ercist.iscas.ac.cn, xuh@nttdata.com.cn, koichi@intellilink.co.jp, kuroiwaj@intellilink.co.jp, okuyama@intellilink.co.jp, matsui_v@valinux.co.jp, kikuchi_v@valinux.co.jp, fernando@intellilink.co.jp, kskmori@intellilink.co.jp, takenakak@intellilink.co.jp, yamaguchi@intellilink.co.jp, ext2-devel@lists.sourceforge.net, shaggy@austin.ibm.com, xfs-masters@oss.sgi.com, Reiserfs developers mail-list Return-path: Received: from dtp.xs4all.nl ([80.126.206.180]:1095 "HELO abra2.bitwizard.nl") by vger.kernel.org with SMTP id S261216AbVFNMvb (ORCPT ); Tue, 14 Jun 2005 08:51:31 -0400 To: Hans Reiser Content-Disposition: inline In-Reply-To: <42AE1D4A.3030504@namesys.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Mon, Jun 13, 2005 at 04:56:58PM -0700, Hans Reiser wrote: > Andreas Dilger wrote: > >Hans, it would probably be preferrable to get ext2-like behaviour where > >action is configurable (see below), > > > > I personally would be annoyed if my > >workstation rebooted if there is a read error from the disk. > > > My concern is that real users don't read their logs and won't notice > that a disk is going bad, and there is no effective method for the > kernel notifying userspace of an error requiring user attention. Speaking from experience (not only by profession, but also as a real user), you figure out pretty fast something is wrong with an Ext[23] filesystem mounted with 'errors=remount-ro'. All kind of file writes go wrong and soon enough you figure out a hardware error is the problem. Umount the filesystem, recover the filesystem image to a new drive, fsck it, recover most of your data, and you're up and running again. Reiserfs will just continue and only issues a few warning in the log, which on its turn will not be read. Only after a few days when things have turn worse you will figure out there's something wrong that requires uses attention. By that time, changes are that the single disk error (be it hardware or software) changed into multiple errors which can make you loose quite some data. I don't want to discredit Reiserfs or Ext[23], but filesystems are not well tested with real disk errors. In my experience a filesystem trying to continue to use a faulty medium usually makes things worse and decreases the probability for a succesful recovery. I'd rather have a filesystem which I can tell to warn me immediately about a problem and not make things worse by trying to continue. A mount option for Reiserfs like Andreas proposed would be a good idea. Erik -- +-- Erik Mouw -- www.harddisk-recovery.com -- +31 70 370 12 90 -- | Lab address: Delftechpark 26, 2628 XH, Delft, The Netherlands