Nagios Plugins

Nagios is a host and service monitor designed to inform you of network problems before your clients, end-users or managers do. It works fine under most *NIX variants. The monitoring daemon runs intermittent checks on hosts and services you specify using external "plugins" which return status information to Nagios. When problems are encountered, the daemon can notify administrative contacts in a variety of different ways (email, instant message, SMS, etc.). Current status information, historical logs, and reports can all be accessed via a web browser.

ConSol* developed a set of Plugins to monitor the status of your Apple Xserves and Apple Xsan. The plugins are free, but use at your own risk.