From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LcOU9-0007l0-MZ for qemu-devel@nongnu.org; Wed, 25 Feb 2009 13:27:57 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LcOU8-0007kU-Uf for qemu-devel@nongnu.org; Wed, 25 Feb 2009 13:27:57 -0500 Received: from [199.232.76.173] (port=40707 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LcOU8-0007kJ-QN for qemu-devel@nongnu.org; Wed, 25 Feb 2009 13:27:56 -0500 Received: from qw-out-1920.google.com ([74.125.92.150]:58369) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LcOU8-0005dL-Dv for qemu-devel@nongnu.org; Wed, 25 Feb 2009 13:27:56 -0500 Received: by qw-out-1920.google.com with SMTP id 4so133709qwk.4 for ; Wed, 25 Feb 2009 10:27:56 -0800 (PST) Message-ID: <49A58DA9.6090502@codemonkey.ws> Date: Wed, 25 Feb 2009 12:27:53 -0600 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [6388] Stop VM on ENOSPC error. References: <49A577FD.60701@codemonkey.ws> <20090225172051.GT24969@redhat.com> In-Reply-To: <20090225172051.GT24969@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" , qemu-devel@nongnu.org Cc: Gleb Natapov Daniel P. Berrange wrote: > On Wed, Feb 25, 2009 at 10:55:25AM -0600, Anthony Liguori wrote: > >> Anthony Liguori wrote: >> >>> Revision: 6388 >>> http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6388 >>> Author: aliguori >>> Date: 2009-01-21 18:59:04 +0000 (Wed, 21 Jan 2009) >>> >>> Log Message: >>> ----------- >>> Stop VM on ENOSPC error. (Gleb Natapov) >>> >>> This version of the patch adds new option "werror" to -drive flag. >>> Possible values are: >>> >>> report - report errors to a guest as IO errors >>> ignore - continue as if nothing happened >>> stop - stop VM on any error and retry last command on resume >>> enospc - stop vm on ENOSPC error and retry last command on resume >>> all other errors are reported to a guest. >>> >>> Default is "report" to maintain current behaviour. >>> >>> >> I recently got burnt by the default being "report". I was doing an >> installation and ran out of disk space. The guest did not do anything >> intelligible with the error reports and froze very hard (as you'd expect). >> >> Any objection to changing to default to enospc? >> > > From a managment POV having QEMU change its state from running to > paused behind our back is hard. You don't want to have to poll on > 'info state' to see if the VM has paused, and QEMU provides us no > async notification for this yet. So at this time, if QEMU auto-pauses > we can't notice this change, and so again it'll just appear to the > user as if it froze. > I appreciate the difficulty but I don't think report is very much better from your perspective if it results in the guest completely freezing. Regards, Anthony Liguori > If we get async notifications available via the monitor, then making > the default enospc is very sensible. > > Daniel >