From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51678) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YBITc-0000Km-9A for qemu-devel@nongnu.org; Wed, 14 Jan 2015 02:34:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YBITY-0007p7-Ah for qemu-devel@nongnu.org; Wed, 14 Jan 2015 02:34:52 -0500 Received: from mail-wi0-x22a.google.com ([2a00:1450:400c:c05::22a]:51092) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YBITY-0007oy-3Q for qemu-devel@nongnu.org; Wed, 14 Jan 2015 02:34:48 -0500 Received: by mail-wi0-f170.google.com with SMTP id bs8so24707013wib.1 for ; Tue, 13 Jan 2015 23:34:47 -0800 (PST) Sender: Paolo Bonzini Message-ID: <54B61C13.9070207@redhat.com> Date: Wed, 14 Jan 2015 08:34:43 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <201501130948157439113@sangfor.com.cn>, <201501131002532239699@sangfor.com.cn> <201501141041046517018@sangfor.com.cn> In-Reply-To: <201501141041046517018@sangfor.com.cn> Content-Type: text/plain; charset=gbk Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] question about live migration with storage List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Zhang Haoyu , qemu-devel Cc: Gleb Natapov , Stefan Hajnoczi On 14/01/2015 03:41, Zhang Haoyu wrote: > Hi, Paolo, > what's advantages of drive_mirror over traditional mechanism implemented in block-migration.c ? > Why libvirt use drive_mirror instead of traditional iterative mechanism as the default way > of live migration with non-shared storage? 1) Being able to choose which block devices are migrated, and whether they are migrated incrementally or not. 2) Finer-grain control the parameters of block migration (dirty bitmap granularity). 3) Block and RAM migration do not share the same socket and thus can more easily be parallelized. Note that 1-2 are not yet supported by libvirt as far as I remember. Paolo