From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=52220 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PsGm9-00005O-IN for qemu-devel@nongnu.org; Wed, 23 Feb 2011 10:37:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PsGkS-0001kg-J3 for qemu-devel@nongnu.org; Wed, 23 Feb 2011 10:35:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42156) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PsGkS-0001ka-7E for qemu-devel@nongnu.org; Wed, 23 Feb 2011 10:35:28 -0500 Date: Wed, 23 Feb 2011 15:33:04 +0000 From: "Daniel P. Berrange" Subject: Re: [Qemu-devel] Re: Strategic decision: COW format Message-ID: <20110223153304.GI26589@redhat.com> References: <4D5BC467.4070804@redhat.com> <4D5E4271.80501@redhat.com> <4D5E8031.5020402@codemonkey.ws> <4D637A20.9020307@redhat.com> <4D650F10.3060900@redhat.com> <4D651858.9040106@codemonkey.ws> <4D652675.1070908@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4D652675.1070908@redhat.com> Reply-To: "Daniel P. Berrange" List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Kevin Wolf , Stefan Hajnoczi , qemu-devel@nongnu.org, Markus Armbruster , Chunqiang Tang On Wed, Feb 23, 2011 at 05:23:33PM +0200, Avi Kivity wrote: > On 02/23/2011 04:23 PM, Anthony Liguori wrote: > >On 02/23/2011 07:43 AM, Avi Kivity wrote: > >>On 02/22/2011 10:56 AM, Kevin Wolf wrote: > >>>*sigh* > >>> > >>>It starts to get annoying, but if you really insist, I can repeat it > >>>once more: These features that you don't need (this is the correct > >>>description for what you call "misfeatures") _are_ implemented in a way > >>>that they don't impact the "normal" case. And they are it today. > >>> > >> > >>Plus, encryption and snapshots can be implemented in a way that > >>doesn't impact performance more than is reasonable. > > > >We're still missing the existence proof of this, but even assuming > >it existed, > > dm-crypt isn't any more complicated, and it's used by default in > most distributions these days. IMHO dm-crypt isn't a generally usable alternative to native built in encryption in qcow2. It isn't usable at all by non-root. If you want to use with plain files, then you need to turn the file into a loopback device and then layer in dm-crypt. It is generally just a PITA to manage. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|