Each domain controller in a domain forest controlled by Active Directory Domain Services includes directory partitions. Directory partitions are also known as naming contexts. A directory partition is a contiguous portion of the overall directory that has independent replication scope and scheduling data. By default, the Active Directory Domain Service for an enterprise contains the following partitions:
- Schema Partition - One per forest. The schema naming context contains the definitions of all objects that can be instantiated in Active Directory. It also stores the definitions of all attributes that can be a part of objects in Active Directory. Every domain controller has one fully writeable copy of the schema directory partition, although schema updates are allowed only on the domain controller that is the schema operations master.
- Configuration Partition - One per forest. It stores forest-wide configuration data that is required for the proper functioning of Active Directory as a directory service. The configuration partition contains replication topology and other configuration data that must be replicated throughout the forest. Every domain controller has one fully writeable copy of the configuration directory partition.
- Domain Partition - One per domain. The domain partition contains the directory objects, such as users and computers, and other objects for that domain. All domain controllers that are joined to the domain share a full writeable copy of the domain directory partition. Additionally, all domain controllers in the forest that host the global catalog also host a partial read-only copy of every other domain naming context in the forest.
Windows Server 2003 introduces the Application Directory Partition, which provides the ability to control the scope of replication and allow the placement of replicas in a manner more suitable for dynamic data.
