Operations Masters Technical Reference

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2

Operations Masters Technical Reference

Operations masters prevent conflicting updates from being made to the Active Directory® Domain Services (AD DS) directory service database by performing specific tasks that no other domain controllers are permitted to perform. Most updates can be made to AD DS on any domain controller and because they are replicated by using a multimaster replication model, all other domain controllers receive the updates.


In Windows Server® 2003 and Microsoft Windows® 2000 Server, the directory service is named Active Directory. In Windows Server 2008 R2 and Windows Server 2008 , the directory service is named Active Directory Domain Services. The rest of this topic refers to AD DS, but the information is also applicable to Active Directory.

However, specific updates, such as password changes, the addition or deletion of a domain or application directory partition, or writing to the AD DS schema, are performed on domain controllers that hold one of five operations master roles to prevent database inconsistencies.

When you install AD DS on the first domain controller in a forest, it automatically assigns five operations master roles to that domain controller. Each of the roles can be transferred to another domain controller at any time.

This subject explains what operations masters are, and how each operations master role functions in Active Directory.

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