The Greenplum DCA is built from four server increments called modules. The DCA starts as a single Greenplum Database module, and can be configured with a maximum of 48 modules, up to a 12 racks
There are three rack hardware configurations, a system rack which contains the first Greenplum Database module and master servers, an aggregation rack, which contains extra switches for multiple rack connectivity and an expansion rack.
The Greenplum Database interconnect and administration networks are configured on a private LAN. Outside access to Greenplum Database and to the Greenplum DCA systems goes through the master servers.