From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:52462) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWSQF-00045w-NQ for qemu-devel@nongnu.org; Mon, 21 May 2012 09:13:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SWSQ9-000178-6y for qemu-devel@nongnu.org; Mon, 21 May 2012 09:13:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55679) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWSQ8-00016Y-VI for qemu-devel@nongnu.org; Mon, 21 May 2012 09:13:09 -0400 Message-ID: <4FBA3F60.9020403@redhat.com> Date: Mon, 21 May 2012 07:13:04 -0600 From: Eric Blake MIME-Version: 1.0 References: <4FB6821A.1080902@redhat.com> <4FBA0AF9.8080705@redhat.com> <4FBA129E.80802@redhat.com> <4FBA19D7.1000806@redhat.com> <4FBA20D6.10507@redhat.com> In-Reply-To: <4FBA20D6.10507@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig21187C9B5833C66E2A707D8E" Subject: Re: [Qemu-devel] Proposal for extensions of block job commands in QEMU 1.2 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Kevin Wolf , Federico Simoncelli , Luiz Capitulino , qemu-devel , Stefan Hajnoczi This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig21187C9B5833C66E2A707D8E Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable On 05/21/2012 05:02 AM, Paolo Bonzini wrote: > Eric, is it a problem for libvirt if a pause or target error during > mirroring causes the job to exit steady state? That means that after a= > target error the offset can go back from 100% to <100%. Libvirt would really like to have events present. If you emit an event on every change from <100% to 100%, and a counterpart event on every revert from 100% back to <100%, then that will help tremendously. For RHEL 6.3, libvirt requires 100% before attempting a drive-reopen. But since this proposal says qemu 1.2 won't even have a drive-reopen, but instead have a new block-job-complete, then libvirt should be okay if block-job-complete gracefully fails any time things are less than 100% (remember, drive-reopen has an attempted effect even if things are less than 100%, which is why libvirt had to pre-filter for that situation, but then again, RHEL never downgraded). In other words, I think downgrading out of steady state is not a problem, as long as events exist to help management track that, and as long as the command to pivot to the destination gracefully requires steady state. >=20 > On the other hand, in other cases it can be desirable (qemu -S, run > streaming before the VM starts). Yes, libvirt would really like a way to be able to start a VM with mirroring active, in order to make it possible to support drive copy on persistent domains. --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enig21187C9B5833C66E2A707D8E 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 Mozilla - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJPuj9gAAoJEKeha0olJ0NquPgH/3n9ibmjvOrCUOWWiKGZGbIK /6Zwpl8hOCyfDQZega5s+fABPzj+ClMFglyLHJ2N9OtVX2oaF/dJq3yGIoPAAbsw tbqzal8mxyhYP1/5zWAhbeP0+3f5tsE3X0on56RlMvbGRyCSbSbzMC6Z9tczh03I +pKJNvfmRswPOtOmN3NawCQNNexXBauDlHmvGVZL8q3Fi7fohHPjZRgeM1crt3GW pBC7LYJOxnrF9dUYMreAU0y7/4dx+Y//6HeajV59HUUBc2pBY5F1P3LzXyZnpo7I kvBYW8au0CSTs4SpbNXzeMN1Mno86KPBv5g+dlbaUYfhL4PByg8aHW/K5YlbMkA= =KrMf -----END PGP SIGNATURE----- --------------enig21187C9B5833C66E2A707D8E--