What is restartable feature of AD DS?

Restartable AD DS reduces the time that is required to perform certain operations. AD DS can be stopped so that updates can be applied to a domain controller; also, administrators can stop AD DS to perform tasks such as offline defragmentation of the Active Directory database, without restarting the domain controller. Other services that are running on the server and that do not depend on AD DS to function, such as Dynamic Host Configuration Protocol (DHCP), remain available to satisfy client requests while AD DS is stopped.


In Active Directory in the Microsoft® Windows® 2000 Server operating system and Windows Server® 2003 operating system, offline defragmentation of the database required a restart of the domain controller in Directory Services Restore Mode. Applying security updates also often required a restart of the domain controller.

In Windows Server 2008, however, administrators can stop and restart AD DS. This makes it possible to perform offline AD DS operations more quickly.

Restartable AD DS adds minor changes to existing MMC snap-ins. A domain controller running Windows Server 2008 AD DS displays Domain Controller in the Services (Local) node of the Component Services snap-in and the Computer Management snap-in. By using either snap-in, an administrator can easily stop and restart AD DS the same way as any other service that is running locally on the server.


The three possible states for a domain controller running Windows Server 2008 are as follows:

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AD DS Started. In this state, AD DS is started. For clients and other services running on the server, a Windows Server 2008 domain controller running in this state is the same as a domain controller running Windows 2000 Server or Windows Server 2003.
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AD DS Stopped. In this state, AD DS is stopped. Although this mode is unique, the server has some characteristics of both a domain controller in Directory Services Restore Mode and a domain-joined member server.
As with Directory Services Restore Mode (DSRM), the Active Directory database (Ntds.dit) on the local domain controller is offline. Another domain controller can be contacted for logon if one is available. If no other domain controller can be contacted, you can use the DSRM password to log on to the local domain controller in DSRM.
As with a member server, the server is joined to the domain. This means that Group Policy and other settings are still applied to the computer. However, a domain controller should not remain in this state for an extended period of time because in this state it cannot service logon requests or replicate with other domain controllers.
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Directory Services Restore Mode. This mode (or state) is unchanged from Windows Server 2003.