From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:34086) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T3Q60-0007HV-6Q for qemu-devel@nongnu.org; Mon, 20 Aug 2012 07:24:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T3Q5z-000663-4f for qemu-devel@nongnu.org; Mon, 20 Aug 2012 07:24:36 -0400 Received: from mail-lb0-f173.google.com ([209.85.217.173]:46653) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T3Q5y-00065w-Ta for qemu-devel@nongnu.org; Mon, 20 Aug 2012 07:24:35 -0400 Received: by lbbgm13 with SMTP id gm13so3050788lbb.4 for ; Mon, 20 Aug 2012 04:24:34 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1344953651-16622-1-git-send-email-benoit@irqsave.net> <20120820101229.GA2218@irqsave.net> Date: Mon, 20 Aug 2012 12:24:33 +0100 Message-ID: From: Stefan Hajnoczi Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC V3 0/9] Quorum disk image corruption resiliency List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?ISO-8859-1?Q?Beno=EEt_Canet?= Cc: kwolf@redhat.com, =?ISO-8859-1?Q?Beno=EEt_Canet?= , stefanha@linux.vnet.ibm.com, qemu-devel@nongnu.org, blauwirbel@gmail.com, anthony@codemonkey.ws, pbonzini@redhat.com, eblake@redhat.com, afaerber@suse.de On Mon, Aug 20, 2012 at 12:23 PM, Stefan Hajnoczi wrot= e: > On Mon, Aug 20, 2012 at 11:12 AM, Beno=EEt Canet wrote: >> Le Tuesday 14 Aug 2012 =E0 16:14:02 (+0200), Beno=EEt Canet a =E9crit : >>> This patchset create a block driver implementing a quorum using m qemu = disk >>> images. Writes are mirrored on the m files. >>> For the reading part the m files are read at the same time and a vote i= s >>> done to determine if a qiov version is present n or more times. It then= return >>> this majority version to the upper layers. >>> When i < n versions of the data are returned by the lower layer the >>> quorum is broken and the read return -EIO. >>> >>> The goal of this patchset is to be turned in a QEMU block filter living= just >>> above raw-*.c and below qcow2/qed when the required infrastructure will= be done. >>> >>> Main use of this feature will be people using NFS appliances which can = be >>> subjected to bitflip errors. >>> >>> This patchset can be used to replace blkverify and the out of tree blkm= irror. >>> >>> usage: -drive file=3Dquorum:n/m:image_1.raw:...:image_m.raw,if=3Dvirtio= ,cache=3Dnone >> >> stefanha: I am wondering what would be needed to do in order to have COR= and streaming working >> with quorum.c ? > > .bdrv_is_allocated()/.bdrv_co_is_allocated() needs to be supported by > block/quorum.c. Have you tried it and found a problem? Just want to confirm you are thinking about image streaming on top of quorum? Or are you thinking about streaming underneath quorum? Stefan