From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56949) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XIx99-0004mn-JU for qemu-devel@nongnu.org; Sun, 17 Aug 2014 05:53:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XIx93-00068z-Eu for qemu-devel@nongnu.org; Sun, 17 Aug 2014 05:53:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53375) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XIx93-00068t-6Y for qemu-devel@nongnu.org; Sun, 17 Aug 2014 05:53:01 -0400 Message-ID: <53F07B73.60407@redhat.com> Date: Sun, 17 Aug 2014 11:52:51 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <53D8FF52.9000104@gmail.com> <1406820870.2680.3.camel@usa> <53DBE726.4050102@gmail.com> <1406947532.2680.11.camel@usa> <53E0AA60.9030404@gmail.com> <1407376929.21497.2.camel@usa> <53E60F34.1070607@gmail.com> <1407587152.24027.5.camel@usa> <53E8FBBD.7050703@gmail.com> <53E92470.60806@linux.vnet.ibm.com> In-Reply-To: <53E92470.60806@linux.vnet.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Microcheckpointing: Memory-VCPU / Disk State consistency List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael R. Hines" , Walid Nouri , qemu-devel@nongnu.org, michael@hinespot.com Il 11/08/2014 22:15, Michael R. Hines ha scritto: > Excellent question: QEMU does have a feature called "drive-mirror" > in block/mirror.c that was introduced a couple of years ago. I'm not > sure what the > adoption rate of the feature is, but I would start with that one. block/mirror.c is asynchronous, and there's no support for communicating checkpoints back to the master. However, the quorum disk driver could be what you need. There's also a series on the mailing list that lets quorum read only from the primary, so that quorum can still do replication and fault tolerance, but skip fault detection. Paolo > There is also a second fault tolerance implementation that works a > little differently called > "COLO" - you may have seen those emails on the list too, but their > method does not require a disk replication solution, if I recall correctly.