From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (ext-mx05.extmail.prod.ext.phx2.redhat.com [10.5.110.9]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o6A1EMr5010095 for ; Fri, 9 Jul 2010 21:14:22 -0400 Received: from ps536.phatservers.com (ps536.phatservers.com [216.17.105.202]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o6A1EDx9023668 for ; Fri, 9 Jul 2010 21:14:13 -0400 Received: from r74-192-24-94.bcstcmta01.clsttx.tl.dh.suddenlink.net ([74.192.24.94] helo=raydesk1.bettercgi.com) by ps536.phatservers.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.66) (envelope-from ) id 1OXOdw-0006py-En for linux-lvm@redhat.com; Fri, 09 Jul 2010 18:14:12 -0700 Date: Fri, 09 Jul 2010 20:14:11 -0500 From: Ray Morris In-Reply-To: (from stuart@bmsi.com on Fri Jul 9 20:01:02 2010) Message-Id: <1278724451.8612.38@raydesk1.bettercgi.com> MIME-Version: 1.0 Content-Disposition: inline Content-Transfer-Encoding: 8bit Subject: Re: [linux-lvm] efficiently copying snapshot data. Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; delsp="Yes"; format="Flowed" To: LVM general discussion and development > > rsync/ > That doesn't do what he wants. He wants to copy only > the COW blocks. The COW blocks being those that are different between the master and the snapshot, correct? Have I been doing it wrong all of these years, because I was under the distinct impression that rsync copied only the differences. Perhaps the confusion is here is whether he wants the destination to include nothing but the changed the blocks, but that doesn't require any new LVM programming. If you want the destination to be a snapshot, only the differences, just take a snapshot on the new machine and rsync from the old snapshot to the new snapshot. A very few blocks might get duplicated because of file level versus block level, but in practice that hasn't seemed to be significant. At least, not for our 160 or so VMs. -- Ray Morris support@bettercgi.com Strongbox - The next generation in site security: http://www.bettercgi.com/strongbox/ Throttlebox - Intelligent Bandwidth Control http://www.bettercgi.com/throttlebox/ Strongbox / Throttlebox affiliate program: http://www.bettercgi.com/affiliates/user/register.php