From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:54716) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UHTmA-00051I-BY for qemu-devel@nongnu.org; Mon, 18 Mar 2013 02:42:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UHTm9-0001Xc-AN for qemu-devel@nongnu.org; Mon, 18 Mar 2013 02:42:30 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:37672) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UHTm8-0001XM-OI for qemu-devel@nongnu.org; Mon, 18 Mar 2013 02:42:29 -0400 Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 18 Mar 2013 12:09:47 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 742E51258059 for ; Mon, 18 Mar 2013 12:13:29 +0530 (IST) Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r2I6gJNi6291824 for ; Mon, 18 Mar 2013 12:12:19 +0530 Received: from d28av01.in.ibm.com (loopback [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r2I6gLEM004511 for ; Mon, 18 Mar 2013 06:42:21 GMT Message-ID: <5146B6F2.3030004@linux.vnet.ibm.com> Date: Mon, 18 Mar 2013 14:40:50 +0800 From: Wenchao Xia MIME-Version: 1.0 References: <5142CCB6.7000004@linux.vnet.ibm.com> <20130315145100.GA17187@stefanha-thinkpad.redhat.com> In-Reply-To: <20130315145100.GA17187@stefanha-thinkpad.redhat.com> Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: Kevin Wolf , Juan Quintela , qemu-devel , Paolo Bonzini , Dietmar Maurer ÓÚ 2013-3-15 22:51, Stefan Hajnoczi дµÀ: > On Fri, Mar 15, 2013 at 03:24:38PM +0800, Wenchao Xia wrote: >> I'd like to add a new way to save vmstate, which will based on the >> migration thread, but will write contents to block images, instead >> of fd as stream. Following is the method to add API: > > Hi Wenchao, > What use cases are there besides saving vmstate to a raw image? > > I'm curious if you're proposing this since there is no "file:" URI or > because you really want to do things like saving vmstate into a qcow2 > file or over NBD. > > Stefan > Hi, Stefan Most used cases would be "raw" and "qcow2", which is flex and can be chosen by user. In this way, existing block layer feature in qemu can be used, such as tagging zeros. I haven't check the buffer/cache status in qemu block layer, but if there is, it can also benefit. User can specify "raw" or "qcow2" according to host configuration, If there is dedicated storage components underlining, he can use "raw" to skip qemu's block layer. -- Best Regards Wenchao Xia