From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36831) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cbSUq-0000pO-OB for qemu-devel@nongnu.org; Wed, 08 Feb 2017 08:41:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cbSUp-0007fL-JC for qemu-devel@nongnu.org; Wed, 08 Feb 2017 08:41:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43648) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cbSUp-0007f7-BJ for qemu-devel@nongnu.org; Wed, 08 Feb 2017 08:41:19 -0500 References: <20170206024535.14624.3001.malonedeb@soybean.canonical.com> <20170208081618.29788.55361.malone@gac.canonical.com> From: Eric Blake Message-ID: Date: Wed, 8 Feb 2017 07:41:16 -0600 MIME-Version: 1.0 In-Reply-To: <20170208081618.29788.55361.malone@gac.canonical.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="JPu7J5kiN5KRGe8lQ4sKSnJGmN2XCObCk" Subject: Re: [Qemu-devel] [Bug 1662050] Re: qemu-img convert a overlay qcow2 image into a entire image List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Bug 1662050 <1662050@bugs.launchpad.net>, qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --JPu7J5kiN5KRGe8lQ4sKSnJGmN2XCObCk From: Eric Blake To: Bug 1662050 <1662050@bugs.launchpad.net>, qemu-devel@nongnu.org Message-ID: Subject: Re: [Qemu-devel] [Bug 1662050] Re: qemu-img convert a overlay qcow2 image into a entire image References: <20170206024535.14624.3001.malonedeb@soybean.canonical.com> <20170208081618.29788.55361.malone@gac.canonical.com> In-Reply-To: <20170208081618.29788.55361.malone@gac.canonical.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 02/08/2017 02:16 AM, wayen wrote: > @Thomas Huth, I just want to reduce the file size of qcow2 overlay imag= e > by this conversion. Are you merely trying to sparsify the file (punch holes on the portion of the file that is not mapped to disk), so that the apparent file size is unchanged, but the actual disk usage is minimized? That's probably already possible (virt-sparsify from libguestfs seems to be able to do it; look at what steps it uses). Or are you asking for a way to defragment the file, so that the apparent size shrinks because all occupied clusters are now contiguous, so that there are no longer any need for holes? The end result is the same amount of disk usage, but right now, the only way to defragment is to convert from one image to a copy; we don't support in-place defragmentation yet. So far, no one has come up with a compelling reason why it is needed, or a patch to implement it, but there's no technical reason why it can't be done. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --JPu7J5kiN5KRGe8lQ4sKSnJGmN2XCObCk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJYmx/8AAoJEKeha0olJ0Nq6BkH/0t2Iw5HlEHzauv0QFAvZMYg OFccQAybPwT2PrGhk9/FaEPD3+lfOjAXRl0XTWj929VgLXsH9OfOgAGuGtkstNgC adTVVs7q2C0XRI+f+fZyYM0zGHMvbbt2uR3c3sqaC9KVY5yYLlnVMci1I0D1a6w8 Sxxl11mkX0kW1uWi2DaQi7+9+Da7fAUnaqL5+UXjiONlOh82gl9aD72sEgP57WaK ir/mKJ0LEOvYWufFjWnVj+XlA0K1bG5cGsZzwPvReivOptlI9fgiExqOiDUP+ZjA Cs7H3CZXU6gs9fTJczJPUyQlQ6H3iip+yvjm+fBEeEXdnyb+CYaFXeDmtsD7kvg= =O2oy -----END PGP SIGNATURE----- --JPu7J5kiN5KRGe8lQ4sKSnJGmN2XCObCk--