From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58565) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMeBN-0003o2-1C for qemu-devel@nongnu.org; Thu, 19 Sep 2013 09:22:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VMeBH-0003Ei-1v for qemu-devel@nongnu.org; Thu, 19 Sep 2013 09:22:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11825) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMeBG-0003As-N7 for qemu-devel@nongnu.org; Thu, 19 Sep 2013 09:22:02 -0400 Date: Thu, 19 Sep 2013 15:21:46 +0200 From: Kevin Wolf Message-ID: <20130919132146.GB3631@dhcp-200-207.str.redhat.com> References: <20130917124413.GA822@stefanha-thinkpad.str.redhat.com> <20130918150527.GA5025@irqsave.net> <20130919082653.GC22814@stefanha-thinkpad.redhat.com> <20130919085750.GA3631@dhcp-200-207.str.redhat.com> <20130919125536.GA12498@irqsave.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20130919125536.GA12498@irqsave.net> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] Merging the quorum block driver List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Beno=EEt?= Canet Cc: Stefan Hajnoczi , qemu-devel@nongnu.org, Stefan Hajnoczi Am 19.09.2013 um 14:55 hat Beno=EEt Canet geschrieben: > Le Thursday 19 Sep 2013 =E0 10:57:50 (+0200), Kevin Wolf a =E9crit : > > Am 19.09.2013 um 10:26 hat Stefan Hajnoczi geschrieben: > > > On Wed, Sep 18, 2013 at 05:05:27PM +0200, Beno=EEt Canet wrote: > > > > Le Tuesday 17 Sep 2013 =E0 14:44:13 (+0200), Stefan Hajnoczi a =E9= crit : > > > > > Hi Benoit, > > > > > Kevin and I had a chance to chat face-to-face and we discussed = what > > > > > concrete changes are necessary to merge quorum (without solving= all the > > > > > other block layers problems at once). > > > > >=20 > > > > > I think quorum could be merged relatively quickly (and without = massive > > > > > BlockFilter investments) by changing the following: > > > > >=20 > > > > > 1. Defining children on the command-line > > > > >=20 > > > > > Existing "filter" drivers use the protocol filename to embed th= eir > > > > > children, for example the blkverify driver. This is a big hack= because > > > > > we have no proper syntax or escaping for the embedded drive def= initions > > > > > in the file=3D option. > > > > >=20 > > > > > This was one of the main arguments against merging quorum. Now= that > > > > > Kevin has implemented driver-specific open options (see > > > > > block/qcow2.c:qcow2_runtime_opts), it is possible for the quoru= m driver > > > > > to open children specific on the command-line: > > > > >=20 > > > > > -drive if=3Dnone,file.driver=3Dquorum,format=3Draw,\ > > > > > file.children0.file=3D/nfs1/test.qcow2,\ > > > > > file.children1.file=3D/nfs2/test.qcow2,\ > > > > > file.children2.file=3D/nfs3/test.qcow2 > >=20 > > By the way, I think he concrete syntax might have to be a bit differe= nt > > so it can be mapped to QAPI for blockdev-add. I think we'll want to u= se > > a JSON list for the children; a mapping to QDict and to the command l= ine > > is yet to be implemented I guess. >=20 > Hi, >=20 > Just to make sure I'll code the right thing; is the following correct ? >=20 > -drive if=3Dnone,file.driver=3Dquorum,format=3Draw,\ > file.children=3D[/nfs1/test.qcow2, /nfs2/test.qcow2, /nfs3/test.= qcow2], \ > file.vote_threshold=3D2 I was thinking more along the lines of: -drive if=3Dnone,file.driver=3Dquorum,format=3Draw,\ file.children[0].file.filename=3D/nfs1/test.qcow2, \ file.children[1].file.filename=3D/nfs2/test.qcow2, \ file.children[1].file.cache.direct=3Don, \ file.children[2].file.driver=3Dnbd, \ file.children[2].file.host=3Dlocalhost, \ file.vote_threshold=3D2 The exact syntax doesn't matter all that much as long as it can be mapped to QAPI, but as you can see this allows specifying detailed options even for the children. I think this is a requirement. Kevin