SQL Server 2012 Administration Joes 2 Pros (R) Volume 1: An Introduction to Administering Databases with Microsoft SQL 2012 (SQL Exam Prep Series 70-4

The value of the database comes from the ability to get the data you want out at a time when it is needed. The role of Database Administrator includes database installation and deployments, and monitoring the system.
Monitoring the system includes monitoring and improving database performance, tracking capacity, and even planning for the future needs based on expanding business requirements.