For information about the troubleshooting scenarios that you might encounter while working with the System Monitoring plug-ins, see the Oracle® Enterprise Manager System Monitoring Plug-in Troubleshooting Guide for Third-Party Database Plug-ins:
http://docs.oracle.com/cd/E24628_01/em.121/e35212/toc.htm
For a complete list of all the metrics contained in this plug-in, see the Oracle Enterprise Metric Guide:
http://docs.oracle.com/cd/E24628_01/em.121/e51915/toc.htm