From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48257) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c98Oc-0000aG-D5 for qemu-devel@nongnu.org; Tue, 22 Nov 2016 05:33:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c98OY-0005uM-HS for qemu-devel@nongnu.org; Tue, 22 Nov 2016 05:33:50 -0500 Date: Tue, 22 Nov 2016 10:33:40 +0000 From: Stefan Hajnoczi Message-ID: <20161122103340.GA5970@stefanha-x1.localdomain> References: <1476971860-20860-1-git-send-email-zhang.zhanghailiang@huawei.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="RnlQjJ0d97Da+TV1" Content-Disposition: inline In-Reply-To: <1476971860-20860-1-git-send-email-zhang.zhanghailiang@huawei.com> Subject: Re: [Qemu-devel] [Qemu-block] [PATCH RFC 0/7] COLO block replication supports shared disk case List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: zhanghailiang Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, kwolf@redhat.com, xiecl.fnst@cn.fujitsu.com, wency@cn.fujitsu.com, Juan Quintela , "Dr . David Alan Gilbert" , mreitz@redhat.com, stefanha@redhat.com, Amit Shah , pbonzini@redhat.com --RnlQjJ0d97Da+TV1 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 20, 2016 at 09:57:33PM +0800, zhanghailiang wrote: > COLO block replication doesn't support the shared disk case, > Here we try to implement it. >=20 > Just as the scenario of non-shared disk block replication, > we are going to implement block replication from many basic > blocks that are already in QEMU. > The architecture is: >=20 > virtio-blk || = =2E---------- > / || = | Secondary > / || = '---------- > / || = virtio-blk > / || = | > | || = replication(5) > | NBD --------> NBD (2) = | > | client || server ---> hidden disk <--= active disk(4) > | ^ || | > | replication(1) || | > | | || | > | +-----------------' || | > (3) |drive-backup sync=3Dnone || | > --------. | +-----------------+ || | > Primary | | | || backing | > --------' | | || | > V | | > +-------------------------------------------+ | > | shared disk | <----------+ > +-------------------------------------------+ > 1) Primary writes will read original data and forward it to Secondary > QEMU. > 2) The hidden-disk will buffers the original content that is modified > by the primary VM. It should also be an empty disk, and > the driver supports bdrv_make_empty() and backing file. > 3) Primary write requests will be written to Shared disk. > 4) Secondary write requests will be buffered in the active disk and it > will overwrite the existing sector content in the buffe This design looks good. I have not reviewed the patches in detail but will review the next revision. Stefan --RnlQjJ0d97Da+TV1 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJYNB8EAAoJEJykq7OBq3PIRYMIAI3nxAskMYYqSln9PPVZBB/m kplTyZoNsBoniKaejMm5OI4m4lYzMbtNc+hhZ2yTIZJd1ssRTxnx/DVeT/55fk6M KtMoya3W8xSA8BAMJe7224AYQ+cKmET52w24nEd9CvuFU2mBMczw10KXp6dMqhP6 3VhTMkr4Y5eRRnjcEb6VYqoUF/iJfrMn7pkTzfYUnrm13cdXqLatLfvoMQrOsn4x Tff1ACGmQC4V+pm8OWuPlJqm167L7kFTCL+9Ar1ybHxUlfFyCy7UkdtWgm84v5tz PR9cynsjGwB0pdC6baNO0BtovqcZu1EZDICxebtAMbAxDNK2AkohAWIipDddyVU= =RYGp -----END PGP SIGNATURE----- --RnlQjJ0d97Da+TV1--