From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56630) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YkqnJ-0006LR-CZ for qemu-devel@nongnu.org; Wed, 22 Apr 2015 05:18:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YkqnG-0004nc-Nr for qemu-devel@nongnu.org; Wed, 22 Apr 2015 05:18:09 -0400 Date: Wed, 22 Apr 2015 10:18:03 +0100 From: Stefan Hajnoczi Message-ID: <20150422091803.GD6581@stefanha-thinkpad.redhat.com> References: <1428055280-12015-1-git-send-email-wency@cn.fujitsu.com> <1428055280-12015-2-git-send-email-wency@cn.fujitsu.com> <20150420153047.GB32653@stefanha-thinkpad.redhat.com> <5535A727.5080402@cn.fujitsu.com> <55366C81.1080202@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="T7mxYSe680VjQnyC" Content-Disposition: inline In-Reply-To: <55366C81.1080202@redhat.com> Subject: Re: [Qemu-devel] [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Fam Zheng , Lai Jiangshan , qemu block , Jiang Yunhong , Dong Eddie , qemu devel , Max Reitz , Gonglei , Stefan Hajnoczi , Yang Hongyang , "Dr. David Alan Gilbert" , zhanghailiang --T7mxYSe680VjQnyC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 21, 2015 at 05:28:01PM +0200, Paolo Bonzini wrote: > On 21/04/2015 03:25, Wen Congyang wrote: > >> > Please do not introduce "+colo" block drivers. This approach = is > >> > invasive and makes block replication specific to only a few block > >> > drivers, e.g. NBD or qcow2. > > NBD is used to connect to secondary qemu, so it must be used. But the p= rimary > > qemu uses quorum, so the primary disk can be any format. > > The secondary disk is nbd target, and it can also be any format. The ca= che > > disk(active disk/hidden disk) is an empty disk, and it is created befor= e run > > COLO. The cache disk format is qcow2 now. In theory, it can be ant form= at which > > supports backing file. But the driver should be updated to support colo= mode. > >=20 > > > A cleaner approach is a QMP command or -drive options that work for a= ny > > > BlockDriverState. > >=20 > > OK, I will add a new drive option to avoid use "+colo". >=20 > Actually I liked the "foo+colo" names. >=20 > These are just internal details of the implementations and the > primary/secondary disks actually can be any format. >=20 > Stefan, what was your worry with the +colo block drivers? Why does NBD need to know about COLO? It should be possible to use iSCSI or other protocols too. Stefan --T7mxYSe680VjQnyC Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJVN2dLAAoJEJykq7OBq3PIn5QIAI66RkFYXtmU9pXszdg7EKd7 958ogfn1+6XkD1w5wYyVoySqNT0W6rhh1XHyJgT+UeTPQfj+qg0m5FsShd4xngBC vms7hXVdDbGEcDhKyEA2b1wLEh1eFosfxdx0JF1sQS+hGWppmrujZGXKLYo/HZBH Knttg/+1E09NJn5l6Z/LG09y+dnAQ1yoxMNw7LDU8QbY6nh0qMh8fg9gr8IWvWYL 6gCpI7br+sUBoGFwxkRXTiB3il4bQrgOznU+QUfh00con0lRq21N7G53W5/FOTLc 9annnomQbHRrvs4ezeIWLHLFp9IBRi4kBnemkWm5Zx6i6cpiLXi7kpgXxWk5L6I= =6XVk -----END PGP SIGNATURE----- --T7mxYSe680VjQnyC--