From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38010) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WBg81-0007XM-NP for qemu-devel@nongnu.org; Fri, 07 Feb 2014 02:45:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WBg7s-0006AG-7L for qemu-devel@nongnu.org; Fri, 07 Feb 2014 02:45:37 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39381) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WBg7r-00069x-SH for qemu-devel@nongnu.org; Fri, 07 Feb 2014 02:45:28 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s177jQgG025174 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 7 Feb 2014 02:45:27 -0500 Received: from dhcp-1-120.tlv.redhat.com (ovpn-116-24.ams2.redhat.com [10.36.116.24]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s177jPLb015461 for ; Fri, 7 Feb 2014 02:45:26 -0500 Message-ID: <52F48F3A.40606@redhat.com> Date: Fri, 07 Feb 2014 09:46:02 +0200 From: Orit Wasserman MIME-Version: 1.0 References: <52F46298.8020602@ozlabs.ru> In-Reply-To: <52F46298.8020602@ozlabs.ru> Content-Type: text/plain; charset=KOI8-R; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] migration question: disk images on nfs server List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org On 02/07/2014 06:35 AM, Alexey Kardashevskiy wrote: > Hi! > > I have yet another problem with migration. Or NFS. > > There is one NFS server and 2 test POWER8 machines. There is a shared NFS > folder on the server, mounted to both test hosts. There is an qcow2 image > (abc.qcow2) in that shared folder. > > We start a guest with this abc.qcow2 on the test machine #1. And start > another guest on the test machine #2 with "-incoming ..." and same abc.qcow2. > > Now we start migration. In most cases it goes fine. But if we put some load > on machine #1, the destination guest sometime crashes. > > I blame out-of-sync NFS on the test machines. I looked a bit further in > QEMU and could not find a spot where it would fflush(abc.qcow2) or close it > or do any other sync so it is up to the host NFS mountpoint to decide when > to sync and it definitely does not get a clue when to do this. > > I do not really understand why the abc.qcow2 image is still open, should > not it be closed after migration succeeded? > > What do I miss here? Should we switch from NFS to GlusterFS (is it always > syncronized)? Or if we want NFS, should we just boot our guests with > "root=/dev/nfs ip=dhcp nfsroot=..." and avoid using disk images in network > disks? Thanks! > For NFS you need to use the sync mount option to force the NFS client to sync to server on writes. Orit > >