From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=56000 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PqXFx-0000yU-Tz for qemu-devel@nongnu.org; Fri, 18 Feb 2011 15:48:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PqXFE-0003f2-Ti for qemu-devel@nongnu.org; Fri, 18 Feb 2011 15:48:06 -0500 Received: from mx1.redhat.com ([209.132.183.28]:21931) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PqXFE-0003ex-JW for qemu-devel@nongnu.org; Fri, 18 Feb 2011 15:48:04 -0500 Message-ID: <4D5EDB61.2090509@redhat.com> Date: Fri, 18 Feb 2011 21:49:37 +0100 From: Kevin Wolf MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: Strategic decision: COW format References: <4D5BC467.4070804@redhat.com> <4D5E4271.80501@redhat.com> <4D5EAFA8.70909@mail.berlios.de> <4D5EC457.506@redhat.com> <4D5ECCE7.2060607@codemonkey.ws> In-Reply-To: <4D5ECCE7.2060607@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Chunqiang Tang , qemu-devel@nongnu.org, Markus Armbruster , Stefan Hajnoczi Am 18.02.2011 20:47, schrieb Anthony Liguori: > On 02/18/2011 01:11 PM, Kevin Wolf wrote: >>> A new file format like fvd would be a challenge for the existing ones. >>> Declare its support as unsupported or experimental, but let users >>> decide which one is best suited to their needs! >>> >> Basically this is what we did for QED. In hindsight I consider it a >> mistake because it set a bad precedence of inventing something new >> instead of fixing what's there. > > I don't see how qcow3 is fixing something that's there since it's still > an incompatible format. > > It'd be a stronger argument if you were suggesting something that was > still fully compatible with qcow2 but once compatibility is broken, it's > broken. It's really more like adding an incompatible feature flag in QED. You still have one implementation for old and new images instead of splitting up development efforts, you still have all of the features and so on. It's a completely different story than QED. Kevin