From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Durgin Subject: Re: qemu-rbd : savevm monitor command don't save vmstate, is it normal ? Date: Wed, 29 Aug 2012 09:15:17 -0700 Message-ID: <503E4015.7050707@inktank.com> References: <3aa58a4b-8f7f-48ac-8ab7-510924be9e2a@mailpro> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:37343 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753857Ab2H2QPU (ORCPT ); Wed, 29 Aug 2012 12:15:20 -0400 Received: by dady13 with SMTP id y13so524850dad.19 for ; Wed, 29 Aug 2012 09:15:19 -0700 (PDT) In-Reply-To: <3aa58a4b-8f7f-48ac-8ab7-510924be9e2a@mailpro> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Alexandre DERUMIER Cc: ceph-devel@vger.kernel.org On 08/29/2012 06:40 AM, Alexandre DERUMIER wrote: > Hi, > > I'm trying to take a full vm state snapshot with savevm monitor command (qemu 0.12rc1 + rbd 0.48.1) > > it seem that vmstate is not saved in the snapshot. (I also don't notice any vm hang during snapshot) > Snapshot of disk is correctly made. AFAIK the only block backend that supports saving the vmstate is qcow2. For rbd, the savevm/loadvm monitor commands are equivalent to 'rbd snap create' and 'rbd snap rollback'. They just save/rollback the disk. > using loadvm monitor command, rollback correctly to disk snapshot but vm hang. If you don't quiesce i/o i.e. via xfsfreeze (it works on the vfs level now, so it's not xfs-specific anymore) before snapshotting a running vm, the fs might require a fsck to be usable. This is only rolling back the disk, and not the memory state, so doing it while the vm is running is likely to cause problems. > starting qemu with -loadvm snapshotname give > kvm: Error -22 while loading VM state > > > Is it normal ? Not implemented ? bdrv_{save|load}_vmstate are not implemented. > > Regards, > > Alexandre