From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:42151) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwvHw-00085b-Sh for qemu-devel@nongnu.org; Thu, 02 Aug 2012 09:18:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SwvHq-0007lM-Te for qemu-devel@nongnu.org; Thu, 02 Aug 2012 09:18:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8526) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwvHq-0007lA-KC for qemu-devel@nongnu.org; Thu, 02 Aug 2012 09:17:58 -0400 Message-ID: <501A7DEF.5000401@redhat.com> Date: Thu, 02 Aug 2012 07:17:35 -0600 From: Eric Blake MIME-Version: 1.0 References: <1343902604-13981-1-git-send-email-benoit@irqsave.net> In-Reply-To: <1343902604-13981-1-git-send-email-benoit@irqsave.net> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig4912ED8981711D33F46F63D8" Subject: Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?B?QmVub8OudCBDYW5ldA==?= Cc: kwolf@redhat.com, pbonzini@redhat.com, =?UTF-8?B?QmVub8OudCBDYW5ldA==?= , qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig4912ED8981711D33F46F63D8 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 08/02/2012 04:16 AM, Beno=C3=AEt Canet wrote: > This patchset create a block driver implementing a qorum using three qe= mu disk s/qorum/quorum/g throughout the series, including subject line > images. Writes are mirrored on the three files. > For the reading part the three files are read at the same time and a vo= te is > done to determine which is the majoritary qiov version. It then return = this s/majoritary/majority/ > majoritary version to the upper layers. > When three differents versions of the data are returned by the lower la= yer the s/differents/different/ > qorum is broken and the read return -EIO. >=20 > 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. >=20 > Main use of this feature will be people using NFS appliances which can = be > subjected to bitflip errors. >=20 > usage: -drive file=3Dqorum:image1.raw:image2.raw:image3.raw,if=3Dvirtio= ,cache=3Dnone How does this fit with snapshots? Does a snapshot of a quorum require passing in three filenames, one for each of the three sources? --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enig4912ED8981711D33F46F63D8 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJQGn3xAAoJEKeha0olJ0NqOfwIAJGR+lYsSFj5o5+9odqAJ6VE LsIcj9g1iA/Spp1iEXWDETty/As3Q0JpekWxlrI4kl4b9HsxG44Enx4lFas2RamS T1xLghlr5tT0LJ9ccKlcL/CVaJ1mm4bDLXntRLK/GXk2BEj1SEPo/7010Y3Ng+E8 bD58CsdRi7CqsqeC5Ne9s3WExDXb7OZYkJzS9WYiK3kHamD9Q2685HA1GdZBZdib p1i3mqI83LtLI4FrWjG/IyeIpY4PCO7K8759C9y6cQv0cBBOBYLb/br7VaDXJ2U9 Dy2gfo5y4k3rap2qfNzc25F5xI49kQCQr5B1LJT6hGJ9x+13XshyA0Frhm4Y7KU= =jL9I -----END PGP SIGNATURE----- --------------enig4912ED8981711D33F46F63D8--