Restartable Active Directory Domain Services (RADDS) is one of those new features in Windows Server 2008 that seems to be relatively unimportant at first glance. However, in certain environments it might be a killer feature. It enables you to stop or restart Active Directory Domain Services (AS DS) on a Domain Controller for maintenance tasks.

For instance, you could do an offline defragmentation or restart the AD DS after a security update. In Windows Server 2003 you had to reboot the whole server or even boot the server into Directory Services Restore Mode. This is still possible with Windows Server 2008, but shutting down the Active Directory Domain Services is certainly much more convenient and reduces downtime. Another important advantage is that other applications running on the DC are not affected.

Component ServicesRestart AD DSThis manual states that you can use the Component Services snap-in to restart AD DS, but I didn’t even find the “Services node” in Windows Server 2008 Beta 3. You can stop or restart the AD DS with the Services snap-in. However, the Domain Controller service mentioned in the manual doesn’t exist either. In Beta 3 the name simply is “Active Directory Domain Services“. When I stopped the AD DS, the Services snap-in also shut down Kerberos Key Distribution Center, Intersite Messaging, DNS Server, and DFS replication.

The manual asserts that you can logon locally with disabled AD DS, like it is possible in Directory Services Restore Mode, but this didn’t work in my test. However, I was able to logon as long as there was another DC online. A DC with disabled AD DS acts like a normal member server. When I started AD DS again, the services snap-in didn’t start the other services that were shutdown before automatically. So, one has to do that manually.

I think this feature is especially interesting for smaller organizations with only one DC. If your DC also hosts other applications, you will certainly appreciate the fact that you don’t have to reboot the whole server for AD maintenance work. In general, however, I wouldn’t recommend using a DC for other purposes.