Munin seems like it would be a much better choice for most people -- both the server and the client are Free and it stores a year of data. What it doesn't do is allow you to drill down into old data -- it's only got static day, week, month and year graphs. You can graph pretty much anything, though.<p><a href="http://munin-monitoring.org/" rel="nofollow">http://munin-monitoring.org/</a>