munin

Munin is a highly flexible and powerful solution used to create graphs of virtually everything imaginable throughout your network, while still maintaining a rattling ease of installation and configuration. This package contains node software. You should install it on all the nodes in your network. It will know how to extract all sorts of data from the node it runs on, and will wait for the gatherer to request this data for further processing. It includes a range of plugins capable of extracting common values such as cpu usage, network usage, load average, and so on. Creating your own plugins which are capable of extracting other system-specific values is very easy, and is often done in a matter of minutes. You can also create plugins which relay information from other devices in your network that can't run Munin, such as a switch or a server running another operating system, by using SNMP or similar technology.