From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33716) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQWo8-0000Hg-Hr for qemu-devel@nongnu.org; Wed, 06 Jun 2018 07:40:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fQWo7-0006he-B6 for qemu-devel@nongnu.org; Wed, 06 Jun 2018 07:40:52 -0400 Date: Wed, 6 Jun 2018 12:40:35 +0100 From: "Richard W.M. Jones" Message-ID: <20180606114035.GG1455@redhat.com> References: <20180524113251.GB4660@redhat.com> <20180528183058.GG2209@redhat.com> <20180528183833.GJ4580@localhost.localdomain> <20180528212054.GH2209@redhat.com> <20180528212510.GC4660@redhat.com> <20180529064415.GA4756@localhost.localdomain> <2b3eef00-f326-c1e6-0e4b-b7602646eec4@redhat.com> <20180606123237.2235ae4a@kitsune.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] storing machine data in qcow images? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz Cc: Michal =?iso-8859-1?Q?Such=E1nek?= , Kevin Wolf , qemu-devel@nongnu.org, stefanha@redhat.com, ehabkost@redhat.com, qemu-block@nongnu.org, "Michael S. Tsirkin" On Wed, Jun 06, 2018 at 01:02:53PM +0200, Max Reitz wrote: > (I'm wondering if we could write a block driver that could provide such > a chunk allocation transparently to qcow2... Note that a qcow2 file > does not need to be continuous, so you could in theory indeed store the > qcow2 file and its data in completely separate places in a tar file.) nbdkit-split-plugin (https://github.com/libguestfs/nbdkit/tree/master/plugins/split). It currently doesn't support resizing although it could do fairly easily. > Yeah, but why make qcow2 that format? That's what I completely fail to > understand. I started off a long reply here, but I think you're right. If we cannot make people decide on and use a proper disk image + metadata container, then it's also unlikely we'll get them to add sensible metadata to their qcow2 images either :-( Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org