Observium is an auto-discovering PHP/MySQL based network monitoring system focused primarily on Cisco and Linux networks but includes support for a wide range of network hardware and operating systems.
Observium has grown out of a lack of easy to use NMSes. It is intended to provide a more navigable interface to the health and performance of your network. Its design goals include collecting as much historical data about devices as possible, being completely auto-discovered with little or no manual intervention, and having a very intuitive interface.
Observium is not yet intended to replace an existing Nagios-type monitoring system, but rather to complement it with intuitive representation of historical and current performance statistics, configuration visualisation and syslog capture.