From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 01 Aug 2007 05:17:28 -0700 (PDT) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with SMTP id l71CHLbm024611 for ; Wed, 1 Aug 2007 05:17:23 -0700 Date: Wed, 1 Aug 2007 22:17:13 +1000 From: David Chinner Subject: Re: Proper method of snapshotting XFS with external log using LVM2 Message-ID: <20070801121713.GY31489@sgi.com> References: <1185737538.12064.44.camel@server.ak.quickcircuit.co.nz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1185737538.12064.44.camel@server.ak.quickcircuit.co.nz> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Mario Becroft Cc: linux-xfs@oss.sgi.com On Mon, Jul 30, 2007 at 07:32:18AM +1200, Mario Becroft wrote: > I am using XFS and LVM2 under Linux. My XFS filesystems have an external > log. > > What is the correct method of creating an LVM2 snapshot of volumes > containing an XFS filesystem with external log? Not sure. I've never tried it. > Do I need to snapshot the main filesystem volume and the log volume? Yes. > Should I be using xfs_freeze to ensure that the filesystem is not > modified between when I create the filesystem snapshot and the log > snapshot? Yes. > Or is there a special procedure for atomically creating both snapshots? > > Or should I not be using an external log? If not, won't this decrease > performance? If it doesn't work, then don't use an external log and yes, it will decrease performance. > In the past I have successfully used xfs_freeze and created separate > snapshots of the filesystem and log volumes. However, I am not sure > whether this is the recommended approach. As long as both snapshots were taken with the one xfs_freeze command, then it shouldbe ok. Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group