From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56796) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dc4je-0007zJ-4O for qemu-devel@nongnu.org; Mon, 31 Jul 2017 03:03:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dc4ja-0003C3-V3 for qemu-devel@nongnu.org; Mon, 31 Jul 2017 03:03:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50162) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dc4ja-0003Bf-Ov for qemu-devel@nongnu.org; Mon, 31 Jul 2017 03:03:22 -0400 Date: Mon, 31 Jul 2017 15:02:46 +0800 From: Peter Xu Message-ID: <20170731070246.GC29971@pxdev.xzpeter.org> References: <1501229198-30588-1-git-send-email-peterx@redhat.com> <1501229198-30588-12-git-send-email-peterx@redhat.com> <2e01324b-73e2-ddb9-7df3-6ae3ec2a7222@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <2e01324b-73e2-ddb9-7df3-6ae3ec2a7222@redhat.com> Subject: Re: [Qemu-devel] [RFC 11/29] migration: new postcopy-pause state List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: qemu-devel@nongnu.org, Laurent Vivier , Andrea Arcangeli , Juan Quintela , Alexey Perevalov , "Dr . David Alan Gilbert" On Fri, Jul 28, 2017 at 10:53:00AM -0500, Eric Blake wrote: > On 07/28/2017 03:06 AM, Peter Xu wrote: > > Introducing a new state "postcopy-paused", which can be used to pause a > > postcopy migration. It is targeted to support network failures during > > postcopy migration. Now when network down for postcopy, the source side > > will not fail the migration. Instead we convert the status into this new > > paused state, and we will try to wait for a rescue in the future. > > > > Signed-off-by: Peter Xu > > --- > > You might want to use scripts/git.orderfile to put .json changes early > in your diffs (interface before implementation makes for easier reviews). Will do. > > > +++ b/qapi-schema.json > > @@ -667,6 +667,8 @@ > > # > > # @postcopy-active: like active, but now in postcopy mode. (since 2.5) > > # > > +# @postcopy-paused: during postcopy but paused. (since 2.10) > > +# > > You've missed 2.10; this should be 2.11. Definitely. It should be for 2.11. > Can this state occur without > any explicit request (ie. old clients may be confused by it), or do you > have to opt-in to a specific migration parameter to inform qemu that you > are aware of how to handle this state? Yes, it can occur automatically, without any operation from user's side. And it does not have a tunable to switch it on/off - it'll always be on (that's my plan, though), since IMHO holding at a paused state is always better than crashing the source directly (that's what we do now - when postcopy encountered network failure, the VM will crash and data will be lost). Thanks, -- Peter Xu