When running the ConfigTool after the install, you will be asked to choose between using the internal Derby database or an external database. The database size used by Web Viewer is small, so from the point of performance it is really no reason to prefer one or other database.
We recommend performing the test installation with the internal Derby database (because it is easier). We recommend using the external database for production due to following reasons:
Please view the Web Viewer Compatibility Supportability Matrix for supported versions of the databases. You will need to log in to view it.
An internal Derby database may be converted to a Db2 database following instructions in RO74120 NEED CONVERSION FROM INTERNAL DATABASE TO DB2