We have a self-sufficient system! It can self-heal and self-adapt. It can work without any humans around. We built Matrix! (http://www.imdb.com/title/tt0133093/) We'll... We're not quite there yet. You will have to observe metrics, look for patterns, create new alerts, and so on. You will have to be behind the system we built so far and continue perfecting it. What we have, for now, is a solid base that you will need to expand. You'll have to use the knowledge you got so far and adapt the examples to suit your own needs.
There are many other combinations and formulas you might want to define as alerts. You might want to perform some actions when CPU usage is too high or when a disk is almost full. I'll leave that to you with a word of caution. Don't go crazy. Don't create too many alerts. Don't saturate humans with notifications and...