Q: What does the Daily Tasks service do?
A: The Daily Task service consolidates and summarizes various statistics. With each scan of a server we request user count, available memory, free disk space, CPU utilization, availability.index, response time, pending mail, etc.
Over the course of the day we might collect each statistic 180 times (assuming an 8 minute scan interval). So if you have 20 or more servers pretty soon you are talking about thousands of records. The value of that information fades over time (who really cares how much memory server A was using at 2:00 3 weeks ago?) so rather than keep all those data points we consolidate and delete.
Some statistics we take the maximum value and others take the average, and some both. For example we'll take the average available disk space for each drive and save that. We'll take the average CPU and keep that. In this way we can produce reports that show trends, such as the report that predicts when servers will run out of disk space. We then delete all the individual data points from a few days ago but keep the summary data point, then start the cycle all over again.