From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mr002msb.fastweb.it ([85.18.95.86]:46928 "EHLO mr002msb.fastweb.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751317AbdHVGL0 (ORCPT ); Tue, 22 Aug 2017 02:11:26 -0400 Subject: Re: =?UTF-8?Q?xfs=5Fmetadump=20as=20a=20backup=20tool?= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 22 Aug 2017 08:11:22 +0200 From: Gionatan Danti In-Reply-To: References: Message-ID: <48895ac1fd87f6ee2dcb09badb787e40@assyoma.it> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Eric Sandeen Cc: linux-xfs@vger.kernel.org Il 21-08-2017 22:11 Eric Sandeen ha scritto: > Short answer is "No," because: > xfs_metadump is only a diagnostic tool. It is not tested or supported > for any other use. > > If nothing else, on a normal live filesystem your metadata and data is > constantly changing; if you replay old metadata over a filesystem, > you'll end up pointing to file data blocks that are incorrect. > > If you really truly have only statically-allocated files from start to > finish, then maybe... > > But more than anything else, the tool was not designed or tested for > anything other than developer diagnostics. > > For disaster recovery, having periodic metadata snapshots might come > in handy from a forensic POV, but I would not rely on this as a > primary part of your normal backup/recovery scheme. Hi Eric, thank for your reply. From xfs_metadump man page is read that the tool should be only used as a debugging aid, but hey - maybe someone used it in more clever ways ;) > If you've already done a proper backup wit tar/rsync/(xfsdump?) then > you have everything you need to restore the filesystem without > resorting to xfs_metadump cleverness, right? Sure, but restoring metadata on a corrupted, but healty, volume would be much faster than restoring both data and metadata. As a first-stop recovery, maybe it was worth a try. But if nobody is doing that, it should not be a good idea... > No, it's not possible to preallocate space on xfs without marking it > as unwritten. Understood. Thanks Eric. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti@assyoma.it - info@assyoma.it GPG public key ID: FF5F32A8