Prevent update-grub from finding LVM based virtual machines

I’m running a debian based XEN box to host various virtual machines. Lately I’ve been having an issue when running update-grub. All the partitions for the virtual machines are found and added to grub:

# update-grub2
Found Debian GNU/Linux (7.7) on /dev/mapper/vg0-vm01-disk
Found Debian GNU/Linux (7.7) on /dev/mapper/vg0-vm02-disk
Found Slackware Linux (Slackware 14.1) on /dev/mapper/vg0-vm03-disk

It’s not a big issue as the xen kernel is still default but it’s annoying. Turns out the fix is simple enough, you have to add one line to /etc/default/grub like this:


After that re-run update-grub.