This is cool. It looks like the developers are reading the comments so I'll add a quick suggestion. Something that I found to be insanely helpful with my own product development was being able to track memory swapping.

I went to great lengths to tune my Java Virtual Machines so that they would work well in a minimum RAM environment. And being able to track swapping was critical for my decision making. Now I can run my product on a 512MB system with 1GB of swap space with no problem. Below is how I'm tracking swapping in real-time.

http://screenshots.gitsense.com/track-swapping.html

Since your solution is focused on capturing a period of time, you'll be able to provide a better view than I am.

With SSD becoming more common for cloud hosting, using swap space in lieu of getting more RAM will probably become more common. And before anybody points out that SSD is still significantly slower than RAM, I know. Depending on your product, using swap on SSD may be practical. I know using swap on amazon's infrastructure wasn't.