From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43668) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XqqTy-0006MI-1H for qemu-devel@nongnu.org; Tue, 18 Nov 2014 16:38:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XqqTo-0000uG-Vz for qemu-devel@nongnu.org; Tue, 18 Nov 2014 16:38:41 -0500 Received: from mail-wg0-x230.google.com ([2a00:1450:400c:c00::230]:40342) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XqqTo-0000uA-OH for qemu-devel@nongnu.org; Tue, 18 Nov 2014 16:38:32 -0500 Received: by mail-wg0-f48.google.com with SMTP id y19so6778600wgg.7 for ; Tue, 18 Nov 2014 13:38:32 -0800 (PST) Sender: Paolo Bonzini Message-ID: <546BBC54.5050900@redhat.com> Date: Tue, 18 Nov 2014 22:38:28 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <546B781B.3070309@gmail.com> <546B791B.6040908@gmail.com> <20141118202805.GC29868@work-vm> In-Reply-To: <20141118202805.GC29868@work-vm> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Tunneled Migration with Non-Shared Storage List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" , Gary R Hook Cc: qemu-devel@nongnu.org On 18/11/2014 21:28, Dr. David Alan Gilbert wrote: > This seems odd, since as far as I know the tunneling code is quite separate > to the migration code; I thought the only thing that the migration > code sees different is the file descriptors it gets past. > (Having said that, again I don't know storage stuff, so if this > is a storage special there may be something there...) Tunnelled migration uses the old block-migration.c code. Non-tunnelled migration uses the NBD server and block/mirror.c. The main problem with the old code is that uses a possibly unbounded amount of memory in mig_save_device_dirty and can have huge jitter if any serious workload is running in the guest. Paolo