I have a user that managed to generate just over 53000 notification messages by sending out a repeating appointment with 'message on everything' selected ..
This managed to generate all those e-mails in a period of about 10 minutes, needless to say our GW server did not like that very much and the POA was running at just over 400% cpu..

Right now its churning to purge these messages out of the DB but is there a quicker less stressful way to clean up something like this ? From what I can tell it is going at about 5 to 10 messages per second.
In a 'have to try something' moment I just deleted the users mailbox which probably did not really do anything by the looks of things.

Thankfully this is the first time in the 8 or so years we use GW, but i can see something like this happen again...

p.s. .. I am sooo glad right now I opted for a dual quadcore for our GW server :-)