EDRM was built with scale in mind. As a solution for DR sites of any size, the EDRM system could be installed as a cluster of App servers that can serve dozens of EnsureDR nodes (called EnsureDR Runners). Each of these Runners can then connect to a controller, with access to the network bubble created within the DR, to test the DR devices.
Depending on the complexity and size of the DR site, the appropriate amount of App servers/EDR-Runners will be installed, will need to be determined so that they will be able to perform the task of invoking and testing the entire Disaster Recovery process with fault tolerance and high availability.
Here are two design solutions for EnsureDR depending on the number of servers you plan to test.