In a standalone deployment (non-clustered), a configuration of DB connection is optional, since embedded Apache Derby DB is used by default and it is sufficient for evaluation. However, configuration of an external DB connection is strongly recommended for production deployment. It is possible to specify common JDBC DB connection attributes (URL, username, password) or a JNDI location of DB DataSource.
In a clustered deployment, at least one node in the cluster must have a DB connection configured. Other nodes may have their own direct connection (to the same DB), or may use another node as a proxy for persistent operations; however, the scheduler is active only on nodes with a direct connection. See Part VI, “Cluster” for details about this feature, this section describes only a direct DB connection configuration.
DB Configurations and their changes may be as follows:
See Database servers for officially supported versions of particular databases.