How is C&U data collected?

I am trying to figure out how C&U data is collected and rolled up. I understand that by default the C & U data collector runs every 10 minutes. But how does the roll up work? I seem to remember that in the case of vSphere it took 20 second samples then rolled them up to the minute, then 5 minutes, 15 minutes, hourly, daily and finally monthly with a 6.months retention. This obviously depends on the provider. The kb article: has the columns broken out by provider but does not explain how the rollup works for each provider.

@ramrexx I had written up a document based on a long discussion I had with another developer. It’s very inside-baseball and needs some cleaning up, but it should give a deep understanding of how C&U rollups work. I’d like to see if we can clean it up even more and make it a solid document.