From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:40130) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T3QNB-0002ia-6H for qemu-devel@nongnu.org; Mon, 20 Aug 2012 07:42:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T3QNA-0002nY-2J for qemu-devel@nongnu.org; Mon, 20 Aug 2012 07:42:21 -0400 Received: from paradis.irqsave.net ([109.190.18.76]:55369) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T3QN9-0002nJ-Pf for qemu-devel@nongnu.org; Mon, 20 Aug 2012 07:42:20 -0400 Date: Mon, 20 Aug 2012 13:42:08 +0200 From: =?iso-8859-1?Q?Beno=EEt?= Canet Message-ID: <20120820114207.GA4197@irqsave.net> References: <1344953651-16622-1-git-send-email-benoit@irqsave.net> <20120820101229.GA2218@irqsave.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: 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: Stefan Hajnoczi Cc: =?iso-8859-1?Q?Beno=EEt?= Canet , 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 Le Monday 20 Aug 2012 =E0 12:24:33 (+0100), Stefan Hajnoczi a =E9crit : > On Mon, Aug 20, 2012 at 12:23 PM, Stefan Hajnoczi = wrote: > > 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 =E9cri= t : > >>> This patchset create a block driver implementing a quorum using m q= emu disk > >>> images. Writes are mirrored on the m files. > >>> For the reading part the m files are read at the same time and a vo= te is > >>> 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 li= ving 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 = blkmirror. > >>> > >>> usage: -drive file=3Dquorum:n/m:image_1.raw:...:image_m.raw,if=3Dvi= rtio,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? >=20 > Just want to confirm you are thinking about image streaming on top of > quorum? Or are you thinking about streaming underneath quorum? I am thinking about streaming with quorum on top of a bunch of backing fi= les. ie: data landing into the higher level backing file living just under quo= rum. Beno=EEt >=20 > Stefan