From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?SXZhbiBMYWLDoXRo?= Subject: Re: raw fs backup/copy Date: Thu, 06 Jan 2011 20:26:10 +0100 Message-ID: <4D261752.9030800@gmail.com> References: <4D25EFA0.9010809@gmail.com> <20110106183507.GA19633@carfax.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: linux-btrfs@vger.kernel.org To: Hugo Mills Return-path: In-Reply-To: <20110106183507.GA19633@carfax.org.uk> List-ID: On 01/06/11 19:35, Hugo Mills wrote: > On Thu, Jan 06, 2011 at 05:36:48PM +0100, Ivan Lab=C3=A1th wrote: >> Is there a reason one can not mount a btrfs and it's byte-for-byte >> copy in parallel, or is the driver just acting silly? >=20 > Probably because both filesystems have identical UUIDs (and labels= ) > and so will (I suspect) end up being identified as the same filesyste= m > by the btrfs code. >=20 > Hugo. >=20 The reason I ask is, that I had a mirror RAID (btrfs on LVM on LUKS on = RAID) across 2 disks. Then I snatched one to take with me when going away for holidays, copied some files on to it and when I came back, I wanted to = get to those files. The problem was, I couldn't mount the fs I took with me= , because a similar fs was already mounted. As it wasn't the root fs, I could unmount it and copy the files on some other fs (though one could use pivot_root, if it was the root fs). It seems to me there are cases, where one would want to mount two copie= s of originally the same filesystem - think of RAID, VMs, distributing fs im= ages on a network, LVM snapshots, backups, etc. -- ivan -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html