What applications or services use AD application partitions Name a couple?

Answer 1

An application directory partition is a directory partition that is replicated only to specific domain controllers. A domain controller that participates in the replication of a particular application directory partition hosts a replica of that partition. Only domain controllers running Windows Server 2003 can host a replica of an application directory partition.

Applications and services can use application directory partitions to store application-specific data. Application directory partitions can contain any type of object, except security principals. TAPI is an example of a service that stores its application-specific data in an application directory partition.

Application directory partitions are usually created by the applications that will use them to store and replicate data. For testing and troubleshooting purposes, members of the Enterprise Admins group can manually create or manage application directory partitions using the Ntdsutil command-line tool.

One of the benefits of an application directory partition is that, for redundancy, availability, or fault tolerance, the data in it can be replicated to different domain controllers in a forest. The data can be replicated to a specific domain controller or any set of domain controllers anywhere in the forest. This differs from a domain directory partition in which data is replicated to all domain controllers in that domain. Storing application data in an application directory partition instead of in a domain directory partition may reduce replication traffic because the application data is only replicated to specific domain controllers. Some applications may use application directory partitions to replicate data only to servers where the data will be locally useful.