symon is a system monitor for FreeBSD, NetBSD, OpenBSD and Linux. It can be used to obtain accurate and up to date information on the performance of a number of systems.

Currently the "suite" consists of these parts:

• symon - lightweight system monitor. Can be run with privleges equivalent to nobody on the monitored host. Offers no functionality but monitoring and forwarding of measured data.
• symux - persists data. Incoming symon streams are stored on disk in rrd files. symux offers systems statistics as they come in to 3rd party clients.
• syweb - draws rrdtool pictures of the stored data. syweb is a php script that can deal with chrooted apaches. It can show all systems that are monitored in one go, or be configured to only show a set of graphs.
• sylcd - symux client that drives CrystalFontz and HD44780 lcds. sylcd shows current network load on a specific host.
• SymuxClient.pm - generic perl symux client. Could, for instance, be used to get the hourly amount of data that was transmitted on a particular interface.