From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:34410) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uc0ao-0007hM-7R for qemu-devel@nongnu.org; Mon, 13 May 2013 17:47:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Uc0an-000824-9x for qemu-devel@nongnu.org; Mon, 13 May 2013 17:47:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26271) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uc0an-000818-28 for qemu-devel@nongnu.org; Mon, 13 May 2013 17:47:37 -0400 Date: Mon, 13 May 2013 22:46:55 +0100 From: "Richard W.M. Jones" Message-ID: <20130513214655.GA9846@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] drive-mirror sync points List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wolfgang Richter Cc: Paolo Bonzini , qemu-devel On Mon, May 13, 2013 at 01:50:00PM -0400, Wolfgang Richter wrote: > Paolo/anyone who knows - > > Are drive-mirror sync points (NBD flush commands) reflecting guest write > barriers? Are guest write barriers respected by drive-mirror? If so, that > would make drive-mirror much more palatable for disk introspection work (a > drop-in usable feature of QEMU!). I'm also interested in this question. Further extensions to this (*not* drive-mirror on its own AIUI) which stefanha is working on should allow libguestfs to perform point-in-time snapshots of images, which will mean that we can do complex and long-running inspection operations on live guests. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top