It’s important to measure the growth of databases so you can plan future space requirements, prepare for time periods when heavy volume traffic is expected, and take action in advance to prevent problems such as highly fragmented databases. It should also help prevent multiple autogrowth events which can negatively affect performance.
The metric data collected can be analyzed over time, so you can calculate the database’s maximum file size in advance, and then configure autogrowth size accordingly.
For more information, see SQL Server Database Growth and Autogrowth Settings.
For details of maximum capacity specifications for SQL Server, see http://msdn.microsoft.com/en-us/library/ms143432.aspx
Rate of change of database file size in MB/hour
Monitors the rate of change of the database file size.