From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LZG7i-0008I4-Cf for qemu-devel@nongnu.org; Mon, 16 Feb 2009 21:55:50 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LZG7d-0008FD-H2 for qemu-devel@nongnu.org; Mon, 16 Feb 2009 21:55:47 -0500 Received: from [199.232.76.173] (port=52377 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LZG7d-0008Ev-AR for qemu-devel@nongnu.org; Mon, 16 Feb 2009 21:55:45 -0500 Received: from ey-out-1920.google.com ([74.125.78.149]:28861) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LZG7c-0004u6-Ri for qemu-devel@nongnu.org; Mon, 16 Feb 2009 21:55:45 -0500 Received: by ey-out-1920.google.com with SMTP id 26so178165eyw.4 for ; Mon, 16 Feb 2009 18:55:42 -0800 (PST) Message-ID: <499A270F.4090205@codemonkey.ws> Date: Mon, 16 Feb 2009 20:55:11 -0600 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH] Revert block-qcow2.c to kvm-72 version due to corruption reports References: <20090213163043.GJ18471@shareable.org> <4995A723.9010208@codemonkey.ws> <20090213190419.GB20328@shareable.org> <4997502D.1080401@codemonkey.ws> <20090215020126.GA9281@shareable.org> <20090215154207.GA24821@shareable.org> <49985CB7.4090803@codemonkey.ws> <4998BB06.1020306@codemonkey.ws> <20090217005244.GD20713@shareable.org> In-Reply-To: <20090217005244.GD20713@shareable.org> 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: qemu-devel@nongnu.org Jamie Lokier wrote: > Anthony Liguori wrote: > >>>> And let's be clear, your data is *not* safe with qcow2. So I don't >>>> consider this to be a show stopping issue. >>>> >>> I beg your pardon? The one format that was recommended for quite a long >>> time now is considered unsafe? >>> >> It's always been that way. It's unsafe for a number of reasons that >> have been discussed at great length. >> > > It sure isn't mentioned in the documentation. > If it was, I would never have used it, and I imagine I'm not alone. > > QEMU might be an emulator project where people expect quirks, but KVM > and Xen are professional virtualisation platforms competing with > VMware. > > It is really not very professional that the documentation places "your > data is not safe" formats on an equal footing with safe formats - > without saying anything about it - and doesn't even recommend one or > the other. > Please submit patches. I don't disagree with you and that is why I'm trying to make this clear now. > That said, maybe Microsoft is doing the same thing - their > documentation happily recommends their VHD format if you're not > concerned about running out of disk space, and it's maybe VHD has > similar corruption windows. > Yeah, it's hard to make a truly reliable format that isn't raw. It basically is the same problem file systems solve and requires either a journal or an fsck step. I'm thinking that this is a problem for other software too. Regards, Anthony Liguori > -- Jamie > > >