[Xen-users] Fixed MAC address causes spurios network connectivity loss.

["JHJE (Jan Holst Jensen)" <jhje@xxxxxxxxxxxxxxx>]

Dear list.

I have been running 5 domUs on a Xen server for two weeks without problems, except for one of the machines. That machine has an erratic network connection and it only occurs when I specify the MAC address. On the other four VMs, Xen chooses a MAC address automatically - in fact I have no "Vif =" lines at all in their configuration files. The machine used to run on a VMware server, therefore the artificial MAC address as you see below:

kernel = "/boot/vmlinuz-2.6-xenU"
memory = 64
name = "sc30"
disk = [ 'phy:vm-disks/sc30-root,sda1,w', 'phy:vm-disks/sc30-swap,sda2,w' ]
root = "/dev/sda1 ro"

# Fixate the MAC address, so flexlm won't complain if we move the VM.
vif = ['mac=00:50:56:00:00:01']

At times, the machine will become unping-able, ssh connections to it will freeze and eventually abort (putty terminal from a Windows client), and then a few seconds or minutes later everything will be working again. While the network loss is going on, I can still ping the machine from domain-0. Is this a misconfiguration of the vif bridge or could it be some unfortunate caching in a network router/switch ?

If I uncomment the "vif = " line in the configuration file the VM's network is rock solid, but I need a fixed MAC address because of the flex license manager that runs on the VM.

I'm running Xen 2.0.6 with Debian Sarge in domain-0, various RedHat domUs.

Cheers
-- Jan Holst Jensen

Principal Research Scientist
Scientific Computing
Novo Nordisk A/S
Denmark

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users