Changing the Database Size 
The database size mainly depends on the size of the data area, which is the set of all data volumes.
Procedure
Use one of the following database tools: Database Studio or Database Manager CLI
Manually Adding or Removing Data Volumes
More information:
Database Studio,
Database Administration in CCMS, Data Area
Automatically Extending the Data Area
More information:
Database Studio, Activating or Deactivating Automatic Extension of the Data Area
Database Manager CLI, auto_extend