From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55758) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UueEo-0007iA-60 for qemu-devel@nongnu.org; Thu, 04 Jul 2013 03:46:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UueEi-0002N5-HL for qemu-devel@nongnu.org; Thu, 04 Jul 2013 03:45:58 -0400 Received: from mail-wg0-x234.google.com ([2a00:1450:400c:c00::234]:43877) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UueEi-0002Jx-5v for qemu-devel@nongnu.org; Thu, 04 Jul 2013 03:45:52 -0400 Received: by mail-wg0-f52.google.com with SMTP id b12so852630wgh.7 for ; Thu, 04 Jul 2013 00:45:50 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <51D52825.5080803@redhat.com> Date: Thu, 04 Jul 2013 09:45:41 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1372386525-23155-1-git-send-email-imain@redhat.com> <1372386525-23155-2-git-send-email-imain@redhat.com> <51D1730C.6030902@redhat.com> <20130703181454.GC7462@gate.mains.priv> In-Reply-To: <20130703181454.GC7462@gate.mains.priv> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH V1 1/2] Implement sync modes for drive-backup. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ian Main Cc: qemu-devel@nongnu.org Il 03/07/2013 20:14, Ian Main ha scritto: >> > >> > Should the source be "bs" for MIRROR_SYNC_MODE_NONE? Also in this case >> > you may want to default the format to "qcow2" instead of bs's format. > I'm not sure that it matters what the source is for NONE. Since we are > copying all new writes, whether they would go to a top-most layer or not > shouldn't matter? It would matter for reads of still-uncopied data, though. You have to read from the topmost layer, not the one below. > As for qcow2 format, there is a 'format' option to the drive-backup API > which specifies the format. I guess we could set the default to qcow2 > instead of the source format? Anyone have any opinions on that? That would be another possibility. Perhaps use qcow2 for top or none, and the source format for full. > I have made the other changes above done. If I don't hear on this issue > soon I'll post another revision. You can go ahead and post anyway (just remember to fix the backing file issue), it is a simple patch on top of what you have. Paolo