From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57704) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WzoMM-0000CE-7K for qemu-devel@nongnu.org; Wed, 25 Jun 2014 10:39:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WzoME-0003oR-4a for qemu-devel@nongnu.org; Wed, 25 Jun 2014 10:39:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:24823) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WzoMD-0003oB-Tp for qemu-devel@nongnu.org; Wed, 25 Jun 2014 10:39:30 -0400 Message-ID: <53AADF17.1050602@redhat.com> Date: Wed, 25 Jun 2014 16:39:19 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <53A9EDAC.6040808@theiggy.com> <53AA06BC.5090604@redhat.com> <53AA69BD.3080106@redhat.com> <53AADA2A.7020607@redhat.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Live Migration with different block devices List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xiongzi Ge Cc: Brian Jackson , qemu-devel@nongnu.org Il 25/06/2014 16:32, Xiongzi Ge ha scritto: > I should make it clearer. I want to use a device for caching for the > guest in host A. Then after the guest migrating to Host B, there is also > a device for caching in Host B. I want to the guest can access the new > cache device in Host B at first automatically. I also want the guest can > access the previous cache device in Host A, if it gets a miss. Here, I > may need to modify some interfaces. Is there a simple way to do this? If your caching is done in the guest, the guest must use O_DIRECT to open the block device. Paolo