From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56045) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XHHBA-0002Fu-Eo for qemu-devel@nongnu.org; Tue, 12 Aug 2014 14:52:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XHHB6-0006Oz-71 for qemu-devel@nongnu.org; Tue, 12 Aug 2014 14:52:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39295) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XHHB5-0006Of-VZ for qemu-devel@nongnu.org; Tue, 12 Aug 2014 14:52:12 -0400 Date: Tue, 12 Aug 2014 19:52:08 +0100 From: "Richard W.M. Jones" Message-ID: <20140812185207.GH14001@redhat.com> References: <20140812184630.GP8471@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140812184630.GP8471@redhat.com> Subject: Re: [Qemu-devel] disk image: self-organized format or raw file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: =?utf-8?B?5ZC05YW05Y2a?= , qemu-devel@nongnu.org On Tue, Aug 12, 2014 at 07:46:30PM +0100, Daniel P. Berrange wrote: > Taking the compression feature - arguably the biggest benefit of that > is when you distribute disk images. eg if someone provides a root disk > image on a web server, using compression in qcow2 can dramatically > lower the download size, while still allowing QEMU to directly run > from that qcow2 file. Sure you could wrap your disk images in gzip > and then convert to your local filesystem at time of use but this > introduces multiple extra steps. It would be nice if qemu could handle xz-compressed files transparently, since (when prepared correctly) these files are seekable. I have written code to do this here: https://github.com/libguestfs/nbdkit/tree/master/plugins/xz 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