Yesterday I was away from the computer and came back to see a series of Nagios alerts, related to DNS. It appears that the Bitfolk dns servers were unable to update a zone from my server. I was unable to login to my server, so went into Xen. It was unable to either shutdown or reboot. When I opened a console window, it was impossible to read as text was scrolling up continuously and rapidly. I had no alternative but to Destroy. A scary option, but within seconds it did the trick and all is running well now.
I have scanned the logs this morning trying to find out what had gone wrong. I realise it was something going haywire and consuming all the resources, but please could anyone give me pointers on how to determine what it was that was behaving so badly?