MySQL with KSE -- Unstable?

I've given MySQL on KSE a couple of tries in production, and I've
run into a problem where threads seem to build up after an hour
or so, depending on load.

The first time I tried it, we were maintaining a load of about 600
threads and 300 queries/second and lasted about three hours
before the thread count went through the roof and MySQL became
unresponsive.

The second time, we were sustaining a load of 1300 threads and
600 queries/second.  This only lasted about 30 minutes.

Each time, upon attempting to restart MySQL without first shutting
down the web cluster that was using it, the server rebooted.
I'm not sure if this was because MySQL got flooded with reconnect
requests, and the machine crashed trying to start up threads
that quickly.

Any ideas?  Has anyone else had success with MySQL on 5.2
with KSE in high-load environments?

Kris Gale