Hi all,

I have a machine with 2 NICs (eth1 & eth2) bonded together in (bond0) connected to the LAN switch and 1 interface (eth3) connected to the WAN switch.

When I set xen to use bond0
(network-script 'network-bridge netdev=bond0')

the bond breaks and eth1 & eth2 are down. If I restart the network, it tells me that bond0 is not the master interface.

Any hints/help would be very much appreciated

hmmm, it must have something to do with the network bridge script for XEN, how is the IP address for this bonded interface aquired? Is it static or DHCP? Have you looked at your system logs to see any error that are being thrown. Try tail dmesg. after you try bridging the bonded interface. The script may not like bridging to a virtual bonded interface. You could try writing a custom script that bridges two devices to eth1 and eth2 then brings up the bonded interface on the host and bond the two virtual NICs in your VM through the guest OS.