NFS lockd/statd lock up network connection

[Ryan Stone]

Well, that does confirm that your system is running out of clusters.
Because you lose all network connectivity I'd suspect a leak, probably in
code exercised by lockd.  I'm afraid that I know absolutely nothing about it
so I can't offer any kind of solution.  Hopefully somebody who does know
something is paying attention.

One thing you could try is setting the tunable kern.ipc.nmbclusters higher
than 25600 -- maybe 40000?  If it's a leak that won't help anything but if
your system just doesn't have enough clusters that will fix it.