From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: virtio implementation? Date: Wed, 18 Jul 2007 20:42:44 -0500 Message-ID: <469EC194.4060202@codemonkey.ws> References: <469C89BD0200005A00027AE1@mcclure.wal.novell.com> <200707190148.21728.arnd@arndb.de> <469EAA2B.40307@codemonkey.ws> <200707190212.25826.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Gerd Hoffmann To: Arnd Bergmann Return-path: In-Reply-To: <200707190212.25826.arnd-r2nGTMty4D4@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Arnd Bergmann wrote: > On Thursday 19 July 2007, Anthony Liguori wrote: > >>> Interestingly, once you have the kernel driver that maps a block device, >>> you can do most of the useful user scenarios by means of /dev/loop >>> and/or device mapper. >>> >> Not quite. Using device mapper to implement something like qcow turns >> out to be pretty painful. >> > > Right. Note that I said 'most scenarios', not all ;-) > > I don't understand enough about qcow to see why you can't do the same > with simple dm snapshots, but I'm sure there is a reason to have it. > The other thing that you would want is "dm-file". The loopback device has some problems with data corruption under certain scenarios. There were patches for dm-file floating around but I haven't seen much activity recently. Regards, Anthony Liguori > Arnd <>< > > ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/