Mastering Active Directory - Second Edition

High availability

High availability is important for any business-critical system in an organization. This is also applicable to domain controllers. On other systems, in order to implement high availability, we need to make software or hardware changes. With built-in fault-tolerance capabilities, Active Directory domain controllers do not need additional changes. A multi-master database, and the replication of domain controllers, allows users to continue with authentication and authorization from any available domain controller at any time.