This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


[Xen-devel] Live migration-delay in gratuitous arp

To: Xen User-List <xen-users@xxxxxxxxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] Live migration-delay in gratuitous arp
From: Virajith Jalaparti <virajith.j@xxxxxxxxx>
Date: Tue, 11 Jan 2011 20:51:23 -0600
Delivery-date: Tue, 11 Jan 2011 18:52:42 -0800
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:message-id:date:from:user-agent:mime-version:to :subject:content-type:content-transfer-encoding; bh=FXvwfGOlb6nVKaUzvRwwvAqBmF2m5Aqg52WoQnAC3L4=; b=CJS4U5OE9+e3HwQ8hYrA2Xgz7wbp4/V99QihYBjpWPsoyYV0BmoSzELLV8FvDxqG+c afgitH0PXFU2E4WtjFWqUIcGGfujGLz6JoCgjPgy4UPsB2vkiRRLkZGpfB/ndTFAfwuP +bI04hOiW2VhslU4P4lNvc1f6J/MwSR/riRyE=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:subject :content-type:content-transfer-encoding; b=ZLNmdmcCFV9LXkMoEJsvNe4vYZukB+NRqqxaFvgEhoVlLvk75s/KIXuCROjTneUgRm CtH3/LO++wPn4KNWq3ymz0sdu63GQjxLhwt1pYD1pbI4DL7NJe2ofQx0YJ+j/ZuFo2r4 s7dwjt0Os3TNezSZQ7mq60NxLwdCwe8xQBsos=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv: Gecko/20101207 Lightning/1.0b2 Thunderbird/3.1.7

I was trying to perform live migration with a VM on a LAN and measure the downtime seen by an application (e.g. ping), the time for which the application cannot communicate with the VM. The application is run on a machine different from those between which the VM is migrated. I noticed that the VM remains unreachable for nearly 1-1.5sec. However the xend.log file says that the time (the delta) for the last round of the migration is around 100msec. So, the VM is actually paused for just around 100msec but the application cannot reach it for 1-1.5sec. I believe this is because of the delay in the gratuitous ARP being sent. Is the implementation such that the ARP is not sent immediately after the migration is finished? Is there an easy tweak (without modifying source code) by which I can correct this or do I have to modify the source code?

I am using Xen from the repos of CentOS 5.5 on a 64bit machine.


Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>
  • [Xen-devel] Live migration-delay in gratuitous arp, Virajith Jalaparti <=