Distributed, enterprise deployments can be of varying size. A basic distributed deployment might improve vRealize Automation simply by hosting IaaS components on separate Windows servers as shown in the following figure.
Many production deployments go even further, with redundant appliances, redundant servers, and load balancing for even more capacity. Large, distributed deployments provide for better scale, high availability, and disaster recovery. Note that the embedded instance of vRealize Orchestrator is now recommended, but you might see vRealize Automation connected to an external vRealize Orchestrator in older deployments.
For more information about scalability and high availability, see the vRealize Automation Reference Architecture guide.