From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58982) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZhJ7p-000796-Tw for qemu-devel@nongnu.org; Wed, 30 Sep 2015 11:16:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZhJ7p-0007Pz-4f for qemu-devel@nongnu.org; Wed, 30 Sep 2015 11:16:57 -0400 References: <56094B0F.7030900@redhat.com> <5609A38F.1070405@redhat.com> <20150929081034.GA3930@noname.str.redhat.com> <560A4F0A.50005@redhat.com> <20150929093531.GD3930@noname.str.redhat.com> <560A6D71.4080007@redhat.com> <20150930144350.GB11943@localhost.localdomain> From: Paolo Bonzini Message-ID: <560BFCD4.1060105@redhat.com> Date: Wed, 30 Sep 2015 17:16:36 +0200 MIME-Version: 1.0 In-Reply-To: <20150930144350.GB11943@localhost.localdomain> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/3] block: mirror - zero unallocated target sectors when zero init not present List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jeff Cody Cc: Kevin Wolf , stefanha@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org On 30/09/2015 16:43, Jeff Cody wrote: > One issue is that QEMU will do mode!='existing' && sync!='full' for > drivers that do not support backing files (raw host devices, for > instance). Yup, this can be used to get a mirror of future operations (the idea was to support things such as antiviruses, where the antivirus connects to QEMU via NBD). I think it's okay to ignore this case, since the resulting image is bogus anyway. What is interesting is only the stream of writes which you can get through NBD. Paolo