FreeBSD 8.0 suddenly freezing

[Charles R Martin]

We have a web host installation using FreeBSD 8.0, Tomcat, and Java.  We 
ship many copies of this, and haven't changed the OS load in several months.

In the last 72 hours, we've had two different systems freeze; they don't 
apparently recognize any interrupts, they won't respond to ping, and 
they require a powercycle to reboot.  We can't easily generate an NMI on 
these boxes.

No crashdumps were generated.

Just on the off chance, does this sound like a familiar -- and 
preferably soluble -- problem?

Regards

Charlie Martin
SGI, Inc.