GPDB modules are a block of servers that host the Greenplum Database. GPDB is always the first module in a DCA. Two additional servers called Masters are included with the first GPDB module. The Primary and Standby Master server serve as the entry point for external connections to the Greenplum Database. The Standby Master server is a warm-standby. In the event of a failure with the Primary Master server, operations will failover to the Standby.
GPDB modules are available in two configurations. The standard configuration offers a mix of high performance and storage, while the capacity configuration offers a large storage capacity while maintaining fast performance. A maximum of 48 GPDB modules can be installed in a DCA.