From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51999) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yv4f7-0002HU-NK for qemu-devel@nongnu.org; Wed, 20 May 2015 10:07:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yv4f4-0007qe-IA for qemu-devel@nongnu.org; Wed, 20 May 2015 10:07:57 -0400 Received: from mail-pd0-f180.google.com ([209.85.192.180]:35275) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yv4f4-0007qI-Ce for qemu-devel@nongnu.org; Wed, 20 May 2015 10:07:54 -0400 Received: by pdea3 with SMTP id a3so70196494pde.2 for ; Wed, 20 May 2015 07:07:52 -0700 (PDT) Message-ID: <555C9533.5080205@ozlabs.ru> Date: Thu, 21 May 2015 00:07:47 +1000 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <555C10A7.4050008@ozlabs.ru> <20150520092118.GB2148@work-vm> In-Reply-To: <20150520092118.GB2148@work-vm> Content-Type: text/plain; charset=koi8-r; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] migration network requirements List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: "qemu-devel@nongnu.org" On 05/20/2015 07:21 PM, Dr. David Alan Gilbert wrote: > * Alexey Kardashevskiy (aik@ozlabs.ru) wrote: >> Hi! >> >> Recent bugreports from our testers at IBM about failed migration across USA >> (for example, from NY to TX) made me wonder - what are the actual basic >> requirements/expectations for migration? > > Oh that's fun. Was it expected to work? Our intranet is not extremely stable :) >> In what network is it normally tested (I use 1Gb/10Gb local network without >> routers)? > > That's also my main test, but in the end it's just a TCP stream, so lots of bandwidth, > not that fussy about latency. > >> Is there any reconnect/restart mechanism if the connection dropped (libvirt, >> qemu)? > > No; one unbroken TCP connection; if you want some reconnect/restart > then tunnel the TCP oversomething that handles that. > >> Is there any document describing network requirements (libvirt, qemu)? > > Don't think so; libvirt has lots of different modes where it can > tunnel stuff as well, see: > http://www.libvirt.org/migration.html#transporttunnel > >> Any ideas are appreciated :) Thanks! > > How is it failing? In libvirt it looks like this (which might be unrelated): Migration: [ 0 %]error: Timed out during operation: cannot acquire state change lock or this (which makes sense): Migration: [ 0 %]error: operation failed: Lost connection to destination host The host kernel network driver can report "BUG: soft lockup" in the network driver. It is from quite old QEMU (2.1-ish) and host kernel though, I just wanted to know $subj and if it really makes sense to spend more time on this. -- Alexey