From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60259) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bpJpR-0007Mw-Mq for qemu-devel@nongnu.org; Wed, 28 Sep 2016 14:43:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bpJpL-0005kb-U7 for qemu-devel@nongnu.org; Wed, 28 Sep 2016 14:43:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51998) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bpJpL-0005kS-NK for qemu-devel@nongnu.org; Wed, 28 Sep 2016 14:43:31 -0400 Date: Wed, 28 Sep 2016 19:43:27 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20160928184326.GM2034@work-vm> References: <20160928180044.GK2034@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] SLIRP migration? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: samuel.thibault@ens-lyon.org, qemu-devel@nongnu.org * Jan Kiszka (jan.kiszka@siemens.com) wrote: > On 2016-09-28 20:00, Dr. David Alan Gilbert wrote: > > Hi Samuel, Jan, > > I'd like to convert SLIRPs migration code to VMState > > and avoid all the qemu_put_/qemu_get_'s - but first I'd like to understand > > when a lot of the slirp migration code makes sense. > > > > I can see that migrating a VM with slirp makes sense (actually more > > commonly saving a VM with slirp to a file); but when that happens > > aren't you likely to lose all the network connections anyway? > > If that's the case then why bother saving all the TCP state? > > > > Under what circumstances do the network connections survive and > > how can I test that? > > I think I never tried this myself back then, nor do I remember any > success story about slirp live migration from the top of my head. It certainly survives - i.e. if you migrate a VM with slirp the VM carries on running, and then you can make a new connection to the VM and it works. Maybe the issue here is that you need to store a lot of state so that the guests view of the dieing connections after migration is correct? Dave > Jan > > -- > Siemens AG, Corporate Technology, CT RDA ITP SES-DE > Corporate Competence Center Embedded Linux -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK