VBD Errors when moving XEN domU between XEN Hosts

Hi Guys,

Today I was migrating a Xen domU between 2 Xen Hosts using Cloudmin 6.1 Pro and started getting the following message when trying to startup the recently migrated system:

Starting up vpsfannit.xtsuniverse.net ...
... failed : Using config file "/mnt/share1/xen/vpsfannit.cfg". Using to parse /boot/grub/menu.lst Error: Device 2501 (vbd) could not be connected. /etc/xen/scripts/block failed; error detected.

If I migrate it back to the host it was just working on there is no issue.

The two host systems are centos 5.5 with Cloudmin GPL for Xen hosting. They are NFS v3 mounting a share from the Cloudmin Pro Master machine.

I did modify the read and write buffer size from default to 8142 as well as modified the mount from soft to hard. But I didn't think that any of those settings would cause an issue with the Xen VBD.

I am a bit baffled, any assistance is greatly appreciated.


Closed (fixed)


I think I figured it out : ). On the Centos XEN Hosts the maxloop default was 8 which I was going over when trying to migrate the domU. I modified the max with the following:

echo 'options loop max_loop=255' >> /etc/modprobe.conf


This has resolved the issue as far as I can tell.


Ok, great .. I will update our documentation to suggest adding this line when setting up a new Xen host, as running out of loopback devices causes problems to Cloudmin itself as well.

Automatically closed -- issue fixed for 2 weeks with no activity.