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Re: [Xen-users] Network Problem after DomU migration

To: ml ml <mliebherr99@xxxxxxxxxxxxxx>, Xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Network Problem after DomU migration
From: Simon Hobson <linux@xxxxxxxxxxxxxxxx>
Date: Tue, 31 May 2011 15:43:50 +0100
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ml ml wrote:

i have two nodes on two switches. When i do a live migration then my
DomU is not reachable anymore.
If i start a ping manually from the DomU console, then its reachable
again. Looks like i need to create traffic so that the Dom0 Network
Stack knows that there is now a DomU running :)

By "reachable" i mean icmp pings to that IP Address.

More likely it's a MAC table caching issue. Each switch (and that includes the virtual switch (bridge) in your Dom0) caches the MAC-port mappings required to forward packets. When you move a device, then the table need to update.

Generating traffic from the DomU will generally cause the switches to update their tables - though some seem to take longer than others, I've seen HP switches take 5 minutes to expire the old mappings.
Simon Hobson

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