Schemas

A schema defines all object classes and attributes that AD DS uses to store data. Each AD DS object has a lot of attributes that need to be populated, such as the name, sAMAccountname, the canonical name, and the location. All of these are controlled by the schema. All domains in a single forest contain a copy of the schema that applies to the forest level. Each change in the schema is replicated from the schema master to every domain controller in the forest. The schema master is typically the first domain controller installed in a forest. An AD DS schema can be changed or modified, but only when necessary. The schema is responsible for information-storage controls, and every untested schema change can potentially affect other applications in the forest that use AD DS. Any schema changes must be performed by the Schema Admins and from the schema master.