Determine average apache2 instance size for tuning

```
ps -ylC apache2 | awk '{x += $8;y += 1} END {print "Apache Memory Usage (MB): "x/1024; print "Average Proccess Size (MB): "x/((y-1)*1024)}'
```

Some stress-tests:
ab -n 1000 -c 5 -C "somecookie=rawr" http://ourwebsite.com/
ab -kc 10 -t 30 http://yourwebsite.com/

EPIC:
https://serverfault.com/questions/383526/how-do-i-select-which-apache-mpm-to-use/383634#383634