“sar” is a Unix command that collect, report, or save system activity information, it is different from other system status command like “top” or “vmstat” that only show real time status only, “sar” in the other hand collect these data so you can find the system state at any time.

This is a draft on configuring Munin to monitor services on a Linux machine, still dirty but published for my reference, if you have question let me know.