The default databases that WSO2 products uses to store registry, user manager and product-specific data are the H2 databases in <PRODUCT_Home>/repository/database as follows:
WSO2CARBON_DB.h2.db: used to store registry and user manager data
These embedded H2 databases are suitable for development, testing, and some production environments. For most production environments, however, we recommend you to use an industry-standard RDBMS such as Oracle, PostgreSQL, MySQL, MS SQL, etc.
You can use the scripts provided with WSO2 products to install and configure several other types of relational databases, including MySQL, IBM DB2, Oracle, and more.