From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36354) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bsFaR-0000XW-6Y for qemu-devel@nongnu.org; Thu, 06 Oct 2016 16:48:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bsFaQ-0001ij-8R for qemu-devel@nongnu.org; Thu, 06 Oct 2016 16:48:15 -0400 Received: from mail-ua0-x22b.google.com ([2607:f8b0:400c:c08::22b]:33850) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bsFaQ-0001hx-2O for qemu-devel@nongnu.org; Thu, 06 Oct 2016 16:48:14 -0400 Received: by mail-ua0-x22b.google.com with SMTP id p25so28862230uaa.1 for ; Thu, 06 Oct 2016 13:48:13 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <42B37FE3-87E1-42CA-A089-B090F37FF7D5@gmail.com> From: Peter Maydell Date: Thu, 6 Oct 2016 13:47:52 -0700 Message-ID: Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] Adding Save States menu items List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: Programmingkid , qemu-devel qemu-devel On 6 October 2016 at 12:59, Eric Blake wrote: > Libvirt also learned that the qemu 'migrate-to-disk' format (used by > 'savevm' or 'migrate') is NOT self-descriptive - in order to fully and > safely revert to an earlier state, you HAVE to store the command line > (or a way to regenerate the command line) that was associated with the > qemu whose state you saved, along with tracking all hotplugs. Since a > mere 'savevm' REQUIRES external information to safely be restored, you > would have to figure out a way to store this additional information > alongside whatever save files you plan on creating (and please don't > change the qcow2 file format to become a dumping grounds for this > additional information). Good point. I think this is a fairly strong argument for keeping the "user friendly" interface to snapshots in the VM management layer, not QEMU itself. thanks -- PMM