From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LL004-0004ih-4e for qemu-devel@nongnu.org; Thu, 08 Jan 2009 13:53:00 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LL003-0004iT-IE for qemu-devel@nongnu.org; Thu, 08 Jan 2009 13:52:59 -0500 Received: from [199.232.76.173] (port=56694 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LL003-0004iO-DV for qemu-devel@nongnu.org; Thu, 08 Jan 2009 13:52:59 -0500 Received: from mx1.redhat.com ([66.187.233.31]:60237) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LL002-0007cW-Vy for qemu-devel@nongnu.org; Thu, 08 Jan 2009 13:52:59 -0500 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n08Iqw49031031 for ; Thu, 8 Jan 2009 13:52:58 -0500 Date: Thu, 8 Jan 2009 18:52:56 +0000 From: "Daniel P. Berrange" Subject: Re: [Qemu-devel] qemu: block.c: introducing "fmt:FMT:" prefix to image-filenames Message-ID: <20090108185256.GA8669@redhat.com> References: <496642BD.4010706@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <496642BD.4010706@redhat.com> Reply-To: "Daniel P. Berrange" , qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Uri Lublin On Thu, Jan 08, 2009 at 08:15:25PM +0200, Uri Lublin wrote: > The purpose of this prefix is to > 1. Provide a way to know the backing file format without probing > it (setting the format upon creation time). > 2. Enable using qcow2 format (and others) over host block devices. > (only if the user specifically asks for it). > > If no fmt:FMT: is provided we go back to probing. I still don't like the fact that this is inventing a second syntax for specifying format that's different to the syntax used for the existing -drive parameter, which is -drive file=/some/path,format=qcow2,....other disk options... > backing file format is qcow2 (even though it's on a host block device) > $ qemu-img create -b fmt:qcow2:/dev/loop0 -f qcow2 /tmp/uuu.qcow2 I'd prefer to see a '-F' flag to specify format of backing file and leave syntax of existing -b arg alone $ qemu-img create -F qcow2 -b /dev/loop0 -f qcow2 /tmp/uuu.qcow2 > force backing file format to raw (no probing) > $ qemu-img create -f raw /tmp/image1.raw 10G > $ qemu-img create -b fmt:raw:/tmp/image1.raw -f qcow2 /tmp/image1.qcow2 $ qemu-img create -F raw -b /tmp/image1.raw -f qcow2 /tmp/image1.qcow2 > Use together with other protocols, e.g. nbd > $ qemu-nbd -v -n --snapshot -t -k /tmp/uuu.socket > fmt:qcow2:/tmp/images/uuu.qcow2 & Should just add a -f arg to qemu-nbd to specify format so it follows qemu-img style, eg $ qemu-nbd -v -n --snapshot -t -k /tmp/uuu.socket \ -f qcow2 /tmp/images/uuu.qcow2 & > $ qemu-img info nbd:unix:/tmp/uuu.socket > $ qemu-system-x86_64 -snapshot -hda nbd:unix:/tmp/uuu.socket > > Or fat > $ qemu-system-x86_64 -hda fmt:qcow2:/tmp/uuu.qcow2 -hdb > fat:floppy:/tmp/images This is unneccessary, since -hda is deprecated, and there's a new -drive arg that already has ability to set format explicitly, as well as many other flags that you need when setting up disks. $ qemu-system-x86_64 \ -drive index=0,format=qcow2,file=/tmp/uuu.qcow2 \ -drive index=1,format=fat:floppy,file=/tmp/images Regards, Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|