You need to install a database and configure it with your CEM software to manage, control, and monitor dataflows.
The EFM Server requrires a relational database. An H2 database is bundled with EFM that is used by default. While this is fine for development and test environments, for production environments, an external database is recommended.
For an external database, you can use either MySQL or PostgreSQL. These topics describe how to install and prepare MySQL and PostgreSQL.