From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41428) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XtENs-0003N3-Np for qemu-devel@nongnu.org; Tue, 25 Nov 2014 06:34:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XtENm-0002P3-IF for qemu-devel@nongnu.org; Tue, 25 Nov 2014 06:34:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47851) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XtENm-0002Os-A8 for qemu-devel@nongnu.org; Tue, 25 Nov 2014 06:34:10 -0500 Date: Tue, 25 Nov 2014 12:34:05 +0100 From: Kevin Wolf Message-ID: <20141125113405.GD4641@noname.redhat.com> References: <2A6E6B95B6E5C146ACE8440760E58185BDC31C30@EXCHANGESERVER.schefczyk.local> <546C8200.4070800@redhat.com> <2A6E6B95B6E5C146ACE8440760E58185BDC31C70@EXCHANGESERVER.schefczyk.local> <546C84C1.5000901@redhat.com> <2A6E6B95B6E5C146ACE8440760E58185BDC31CD0@EXCHANGESERVER.schefczyk.local> <546CAF2F.4090103@redhat.com> <546CBAB5.8050202@redhat.com> <2A6E6B95B6E5C146ACE8440760E58185BDC32099@EXCHANGESERVER.schefczyk.local> <546CDDC7.2070805@redhat.com> <2A6E6B95B6E5C146ACE8440760E58185BDC4FF51@EXCHANGESERVER.schefczyk.local> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="HcAYCG3uE/tztfnV" Content-Disposition: inline In-Reply-To: <2A6E6B95B6E5C146ACE8440760E58185BDC4FF51@EXCHANGESERVER.schefczyk.local> Subject: Re: [Qemu-devel] "File too large" error from "qemu-img snapshot" (was Re: AW: Bug Repoting Directions Request) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Prof. Dr. Michael Schefczyk" Cc: Paolo Bonzini , qemu-devel --HcAYCG3uE/tztfnV Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Am 22.11.2014 um 18:02 hat Prof. Dr. Michael Schefczyk geschrieben: > Dear All, >=20 > after some trying, my impression is that the following steps do work with= plain Centos 7: >=20 > virsh snapshot-create-as VM backsnap > qemu-img convert -f qcow2 -s backsnap -O qcow2 VM.img backup.img > virsh snapshot-delete VM backsnap >=20 > Am I on the right track with these commands? I won't tell you that you're bound to break your image with this sequence, because chances are that you won't break it. (In practice, this happens to work in most cases, because the essential snapshot metadata generally isn't written to without explicit user actions on that snapshot.) But you're violating the rule of "one writer or many readers", so as far as qemu is concerned, we won't be careful to avoid breaking this setup. Don't blame us if it fails one day. With the QMP solutions (either drive-backup or snapshot/commit) you're using official APIs, so I'd encourage you to use these. Kevin --HcAYCG3uE/tztfnV Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJUdGktAAoJEH8JsnLIjy/WaXsP/0+BBCtbFt/ERlrqBkYcOvDh y67N/Z3+Ns8jxCOeaRALX9t0XSYfYueRv3DOli0vVUpdmvd4irHVGILAtDcf3J4M ebU9/Og+0p2JsGyKgf3pB98wxp/MkvCbLy7D8klPYnGkqbMlRrEa8uok6pVAsi8W ZoUsFkn+n2XdW7LULh3vonCGW6Dg090um5G5u++NLa7Se04Y9wojcaFriNwl9H9g xsXgOA5uEPtPhKWte1HUgjKsOVeXpmyE5UXA90Jzs+Ng3dhhWi/up/FDXxs9MNK3 MSorHpL2mtpmoq0LGHLp81T+xtOqNKOA1ECwLd2IFMoJl4jlSIcBBBLyD2fzTM5y SNXAfWBRllVBeE0t+kpRfxpe8VfBgGH5l2yyWEjexHvzm4oHItEpOCq5JEdYv41Y CNjJxaCA5a4gn6fKEonPLX9fWb9IsM/t+I2YoH5P94gqF5GJdcy/6/UeY/MaqLv4 iMZbgJXmtoJvtM3cD4W3TSsulqbQYKSKW6uw+1/ZnckHaQHXy1AXvQWKpne/PwzZ qR5Qy2Ki64upT/fGUFo/FG3p7Qyx4mR5aZm6VD4UexqXuesc8ItYpHyt8VDWNZQk RRXHoqy9165jr5fmSBx6w8vbwKJcRz97Zjn12WX55H2qo4HGTo20JxfAsJuSGXsK Jq4WiiLAtaGHS0YTnPav =TZeU -----END PGP SIGNATURE----- --HcAYCG3uE/tztfnV--