On Tue, 25 Oct 2011, Roger Pau Monné wrote: [snip]
It's probably not related to Xen, but I'd recommend trying a newer -current kernel.I think it's the same problem as the one reported by Christoph Egger on PR #40726, and AFAIK it seems like it's not solved.
Yes, it's crashed like this for years for me.
Also the vnd(4) man page states that "The vnd driver does not work if the file does not reside in a local filesystem.", which is a problem if the user wants to perform live migrations between NetBSD Dom0 Xen servers. I don't know how how to fix this, but I think it is important to have this feature.
It would be good if it worked, but there are alternatives such as istgt/iscsi-target + iscsi-initiator. The nice thing about these is that they offer an easy migration route - the same files you are trying to use with NFS can be used as the backing files for the iscsi target software (and will work as sparse files too).
-- Stephen