Your relational database is a critical element for performance and disaster recovery. The provided Derby database, while sufficient for proof-of-concept work, is generally insufficient for the enterprise. Full-featured databases like Oracle, MS SQL Server, or MySQL are better options. Ideally, the database—whichever is used—should be configured for high-availability, high-performance, and be backed-up regularly.
10-20 GB of database storage should be sufficient for most environments. For Oracle, an architecture based on Oracle RAC is recommended; for Microsoft SQL Server, a clustered configuration is preferred; for MySQL, utilize MySQL Cluster.
