Kernel spits out

May 23 00:00:32 katiska /kernel: mb_map full

And network interface starts dropping packets.  Occasionally a packet
or two gets through, as sometimes nfs says is alive again, and even a
login gets though.  A couple of hours later the connections die
completely.

Fix: 

Don't know, but I assume it is a too small fixed-size table
somewhere, and probably a leak somewhere else.
How-To-Repeat: 
	Don't know, but suspect high load.