Looks like the downtime was caused by runaway spamassassins again. Luckily
the new watchdog timer is bringing the box down and back up, though it seems
to take a few hours.
Sitting here watching spamassassin for the last 30 minutes nothing has gone
wrong. Perhaps it was something else? Needless to say I am not happy with this
situation but I haven't much time to debug it. Hopefully the box should stay
up for a while now. We'll see.