From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 11 Feb 2008 14:03:33 -0800 (PST) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with SMTP id m1BM3Mnc016077 for ; Mon, 11 Feb 2008 14:03:26 -0800 Date: Tue, 12 Feb 2008 09:03:39 +1100 From: David Chinner Subject: Re: Data safety horror stories? Message-ID: <20080211220339.GZ155407@sgi.com> References: <1202748389.28320.1236240801@webmail.messagingengine.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1202748389.28320.1236240801@webmail.messagingengine.com> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: "Felix E. Klee" Cc: xfs-oss On Mon, Feb 11, 2008 at 05:46:29PM +0100, Felix E. Klee wrote: > I heard that, in case of a power failure, XFS may lose data, even data > that was already existing on the disk. For example, I heard horror > stories of files being overwritten with zeros. > > Are those stories true? > > If so: > > * Do you recommend not using XFS on devices that may frequently fail due > to power failure? Depends on how much you care about your system and data. I use XFS on write-cache enabled SATA drives without barriers with no UPS (yes, it's unsafe!) and I lose power at least once a week. I haven't had a data loss or corruption in over two years and tens of power failures.... > * Is it possible to find out what files have been damaged? Not easily. > If not, > will only files be affected that have been changed during the last > couple of hours? Last few seconds before the power fail, actually. > * Are there options to increase data safety? Should one run a regular > "sync" in a cron job? If you are truly paranoid - turn off drive caching and mount with the 'wsync' option. > * Is it unsafe to use XFS in a virtual machine which may sometimes be > terminated without proper shutdown? I do that all the time, too. Corruption is rare and usually as a result of some bug in the code I'm testing ;) > I currently am using XFS under Ubuntu 7.10 (Kernel 2.6.22), running in a > virtual machine (VMware) under Windows. The XFS file system is in a > native partition on a second HDD. Should be just fine. If you are really concerned - test it. Cheers, Dave. > > -- > Felix E. Klee > Jabber/Google Talk: feklee@jabber.org, SIP: 9779619@sipgate.de > ICQ: 158124695, Yahoo!: feklee, AIM: felix.klee@inka.de > Gizmo: felixklee, Skype: felix.klee > -- Dave Chinner Principal Engineer SGI Australian Software Group