From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shu Ming Subject: Re: [Qemu-devel] Stalls on Live Migration of VMs with a lot of memory Date: Wed, 04 Jan 2012 09:38:32 +0800 Message-ID: <4F03AD98.7020700@linux.vnet.ibm.com> References: <032f49425e7284e9f050064cd30855bb@mail.dlh.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org To: Peter Lieven Return-path: Received: from e28smtp01.in.ibm.com ([122.248.162.1]:50694 "EHLO e28smtp01.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751485Ab2ADBim (ORCPT ); Tue, 3 Jan 2012 20:38:42 -0500 Received: from /spool/local by e28smtp01.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 4 Jan 2012 07:08:39 +0530 Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q041cZhU3342340 for ; Wed, 4 Jan 2012 07:08:35 +0530 Received: from d28av02.in.ibm.com (loopback [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q041cYKr027237 for ; Wed, 4 Jan 2012 12:38:35 +1100 In-Reply-To: <032f49425e7284e9f050064cd30855bb@mail.dlh.net> Sender: kvm-owner@vger.kernel.org List-ID: On 2012-1-4 2:04, Peter Lieven wrote: > Hi all, > > is there any known issue when migrating VMs with a lot of (e.g. 32GB) > of memory. > It seems that there is some portion in the migration code which takes > too much time when the number > of memory pages is large. > > Symptoms are: Irresponsive VNC connection, VM stalls and also > irresponsive QEMU Monitor (via TCP). > > The problem seems to be worse on 10G connections between 2 Nodes (i > already tried limiting the > bandwidth with the migrate_set_speed command) than on 1G connections. Is the migration accomplished finally? How long will that be? I did a test on VM with 4G and it took me about two seconds. > > The problem also seems to be worse in qemu-kvm-1.0 than in > qemu-kvm-0.12.5. > > Any hints? > > Thanks, > Peter > > -- Shu Ming IBM China Systems and Technology Laboratory