The Database Agent is a standalone Java program that collects performance metrics about your database instances and database servers. You can view these performance metrics in the Metric Browser of the Controller UI. 

To start monitoring your database, you must first install the Database Agent. You may want to install multiple agents for the following reasons:

• You have databases on multiple networks that are not accessible by one machine. 
• You have multiple SQL Server instances that each require different credentials, and you want to connect to them through Windows Authentication.
• You want one or more agents to back up a primary agent. Backup agents ensure that your database instances are continually monitored during agent failure or machine downtime.