In a small project requiring three domains, how many Domain Controllers (DCs) should be included for reliability?

In a small project that necessitates three domains, including a sufficient number of Domain Controllers (DCs) is crucial for ensuring reliability and redundancy. The principle behind this is to have at least one Domain Controller for each domain to support its operation while additionally providing backup in the event of a failure.

For reliability, it is generally recommended to have at least two Domain Controllers per domain. This ensures that if one DC becomes unavailable, the other can continue to manage authentication, access control, and directory services without disruption. Therefore, with three domains, having two DCs per domain would lead to a total of six Domain Controllers. This setup guarantees that there are always available services and redundancy in case of any hardware or software failures, which enhances the overall reliability of the network infrastructure.

Thus, for a project that encompasses three domains, the inclusion of six Domain Controllers is the best choice to optimize reliability and maintain continuous operations.