What is Restartable Active Directory Domain Services in Windows Server 2008/R2? What is this feature good for?

One of the major problems that we faced since windows NT/2000 that the server needs to restart to apply some settings and it is not recommended on life environment to do so often. So Microsoft tries to reduce the cases of needing of restart. But the more the setting get deep the more we need restart to apply this so this new feature to reduce this on the level of directory services.

Restartable AD DS reduces the time that is required to perform offline operations such as offline defragmentation. It also improves the availability of other services that run on a domain controller by keeping them running when AD DS is stopped. In combination with the Server Core installation option of Windows Server 2008, restartable AD DS reduces the overall servicing requirements of a domain controller.

In Windows 2000 Server Active Directory and Windows Server 2003 Active Directory, you must restart the domain controller in DSRM when you perform offline defragmentation of the database or apply security updates. In contrast, you can stop Windows Server 2008 AD DS as you stop other services that are running locally on the server. This makes it possible to perform offline AD DS operations more quickly than you could with Windows 2000 Server and Windows Server 2003.