WSO2AM_DB: For API-M-specific data.
WSO2MB_DB: For message brokering data.
WSO2METRICS_DB: For storing data for metrics monitoring.
Note that the metrics database is disabled by default in API-M 2.6.0. However, if you need to work with metrics enable the metrics DB. For more information, see Enabling Metrics and Storage Types.
For instructions on changing the default Carbon database, see Changing the Carbon Database in the WSO2 Product Administration Guide.