Recently I had a problem while working with SLES - Suse Enterprise Linux.
During reboot it just hanged same thing was going on while shutting down with halt -p.
From the messages appearing on screen I have seen that it has trouble with un mounting nfs shares.
The problem was that Suse was first bringing down network interfaces than trying to umount nfs shares.
I could either spend time trying to fix os (add umount somewhere to pre halt operations) or I could do:
- umount -a (so all resources that are not being used will be unmounted) and then halt -p or reboot
- do reboot -f instead (reboot with force does not care if nfs resources are mounted)
So I have decided not to spend time on fixing SUSE/SLES and do umount or reboot -f.
Overall my experience with SLES/SUSE is that they did really nice installer ... but apart from that things that should work out of the box don`t.