I was testing a couple of caching software to stablize the site. Wopular used to crash 3-8 times a day. I had thought the main culprit was mysql because whenever resources become low, there is a logjam of queries waiting to be processed. They eventually pile up and consume all available resources and crash the site. Since I was able to set the server to reboot whenever it's near the melting point I didn't mind it too much because it only takes about 2-5 minutes.