I've been playing with OpenBSD for a little while now, and really love it
when I need to throw together a quick firewall, web server, dhcp server,
etc. I've got on firewall that I've been using for a little while now,
OpenBSD 4.6, running on a VMWare ESXi box. It normally performs fine, and it
is doing some NAT and firewall functions with PF. I've pushed quite a few
packets through it and am impressed with the performance I am able to get
out of it. 

However, it seems like roughly every 2-3 weeks, I'll experience an issue
with it where it will stop responding. I can still ping the machine, but it
won't forward any packets, accept SSH connections, or respond to basically
anything. If I check on my VMWare host machine it is showing 100% cpu
utilization, and I am unable to access the console directly through VMWare. 

Performing a reset through VMWare fixes it and it runs fine again, for a few
weeks, until the same problem occurs. After resetting the box I check out
all the log files but I have never been able to see anything that even
remotely seems relevant to what could have been happening.  I know of no way
to see what processes are running and eating up the cpu when this occurs,
since I can't get it to respond to anything. I am hoping someone may be able
to help point me in the right steps of where to begin troubleshooting this--
I am a fairly experienced Windows admin, but still pretty new to the BSD
world, but am trying my best to adopt it wherever possible!

Thanks in advance!