From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:58907) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TrguP-0002Ce-AT for qemu-devel@nongnu.org; Sat, 05 Jan 2013 22:28:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TrguO-0008It-12 for qemu-devel@nongnu.org; Sat, 05 Jan 2013 22:28:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58846) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TrguN-0008Il-Pn for qemu-devel@nongnu.org; Sat, 05 Jan 2013 22:28:23 -0500 Message-ID: <50E8EF52.5080507@redhat.com> Date: Sat, 05 Jan 2013 20:28:18 -0700 From: Eric Blake MIME-Version: 1.0 References: <50D2CC22.1060900@linux.vnet.ibm.com> <50D3C8AF.7050506@linux.vnet.ibm.com> <20130104173550.GB9481@stefanha-thinkpad.redhat.com> <87623ca7up.fsf@elfo.mitica> <50E7E27A.8050209@linux.vnet.ibm.com> In-Reply-To: <50E7E27A.8050209@linux.vnet.ibm.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig0837F699C565F211E0AAC7AD" Subject: Re: [Qemu-devel] [RFC] lively write vmstate with predictable size List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wenchao Xia Cc: Anthony Liguori , Pavel Hrdina , quintela@redhat.com, Stefan Hajnoczi , qemu-devel , Paolo Bonzini , Dietmar Maurer This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig0837F699C565F211E0AAC7AD Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 01/05/2013 01:21 AM, Wenchao Xia wrote: > I guess migration to file makes vm stopped, and lack a step > to take snapshot in the end of migration, also the usage seems > strange makes me feel something is lacking. I'd like to > have: > 1 take blk snapshot internal/external lively. > 2 take vmstate snapshot internal/external lively. > 3 combination. Libvirt 1.0.1 can already do external live snapshots - it does a live migration to file, and when that finally converges enough to pause, there is less than a second of downtime when libvirt then follows up with an external disk snapshot and then resumes the guest. Of course, this approach requires multiple files, and there is no way to take an internal snapshot with current QMP support. And the point remains in this thread that a live migration to file takes more space than a paused migration, in part because earlier portions of the migration stream are revisited later in the stream as memory pages continue to be touched during the live migration. So a new format for seekable migration to file, different than current migration being usable over a fifo, may indeed allow for less disk space and faster booting when reverting to that vmstate. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enig0837F699C565F211E0AAC7AD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with undefined - http://www.enigmail.net/ iQEcBAEBCAAGBQJQ6O9SAAoJEKeha0olJ0NqrLcIAIzLIBu6ci/nTWs+DhkPX0gd OhD6nP1dfXJUIIBboPGE9KN7lq5qLrkFYXFZlpLtcfBFBTNldL6kav2vdzsQhuxh xtYI765oqMX8jNLkfEbKOIfhDpozONTDIduGepiLGxRXtXYWwn0otfKybdKW0uoV 4i/mFVIbamOD8NAz7pjLk+pDSNmA5Bxop0TmHkZjLlwO5ZmIZ8L0osYzK7x6+fmi gYC3ftZFS32o62L5lgpf0XJ+eFd0XR5BbiXJ+HTH1WktbmqMXESfBAfJ+2d+3iwW 9b7WgtXq5C0Jt6SySRBuSyG3uJbsQO3mC3R8e7j+iqVEAEDRtk7hrxworpVdDeA= =AXPz -----END PGP SIGNATURE----- --------------enig0837F699C565F211E0AAC7AD--