From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:40500) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S0VIT-0000wX-Ck for qemu-devel@nongnu.org; Thu, 23 Feb 2012 04:49:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S0VIN-0007RW-Ny for qemu-devel@nongnu.org; Thu, 23 Feb 2012 04:49:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:14389) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S0VIN-0007RS-D9 for qemu-devel@nongnu.org; Thu, 23 Feb 2012 04:49:03 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q1N9n2Ef012034 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 23 Feb 2012 04:49:02 -0500 Message-ID: <4F460B8B.1060302@redhat.com> Date: Thu, 23 Feb 2012 10:48:59 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <217d6e69-baf0-4f10-8199-87e2ea7353fb@zmail16.collab.prod.int.phx2.redhat.com> In-Reply-To: <217d6e69-baf0-4f10-8199-87e2ea7353fb@zmail16.collab.prod.int.phx2.redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/3] Add nocreate option to snapshot_blkdev List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Federico Simoncelli Cc: kwolf@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org On 02/23/2012 10:39 AM, Federico Simoncelli wrote: > I agree on the fact that using snapshot_blkdev is a misnomer but at > the same time I like very much how blkmirror is modular and it can > be used as a regular image filename. True, on the other hand if we add this we will have to keep it forever. I'm worried that blkmirror does not satisfy _all_ mirroring needs, for example you cannot use block_stream to copy from the source to the destination, so perhaps in the future we want to change it to something else. So while I appreciate the easier debugging, I'm afraid that we'll regret adding a command-line-visible feature. > I'm worried that making it explicit with a "--mirror" option would > take away its flexibility. > What about adding block_reopen and extending the blkmirror string: > > (qemu) block_reopen ide-hd0 \ > blkmirror:qcow2:/tmp/src/hd0snap1.qcow2:/tmp/dst/hd0snap1.qcow2 > > so that the format is passed as first argument (and if it's empty we > would use the auto-detection). No, the format of the source and destination should be independent. It would be nice to have something like this: blkmirror:src=...,dst=...,srcformat=...,dstformat=... but commas are a pain because they need escaping. Paolo