We will discuss on the directory partitions in active directory and its purpose served in the windows domain environment. The active directory database is logically separated into directory partitions:
• Schema partition
• Configuration partition
• Domain partition
• Application partition
Each partition is a unit of replication, and each partition has its own replication topology. Replication occurs between replicas of directory partition. Minimum two directory partitions are common among all domain controllers in the same forest: the schema and configuration partitions. All domain controllers which are in the same domain, in addition, share a common domain partition.
1. Only one schema partition exists per forest.
2. The schema partition is stored on all domain controllers in a forest.
3. The schema partition contains definitions of all objects and attributes that you can create in the directory, and the rules for creating and manipulating them.
4. Schema information is replicated to all domain controllers in the attribute definitions.
1. There is only one configuration partition per forest.
2. Second on all domain controllers in a forest.
3. The configuration partition contains information about the forest-wide active directory structure including what domains and sites exist, which domain controllers exist in each forest, and which services are available.
4. Configuration information is replicated to all domain controllers in a forest.
1. Many domain partitions can exist per forest.
2. Domain partitions are stored on each domain controller in a given domain.
3. A domain partition contains information about users, groups, computers and organizational units.
4. The domain partition is replicated to all domain controllers of that domain. All objects in every domain partition in a forest are stored in the global catalog with only a subset of their attribute values.
1. Application partitions store information about application in Active Directory.
2. Each application determines how it stores, categorizes, and uses application specific information. To prevent unnecessary replication to specific application partitions, you can designate which domain controllers in a forest host specific application partitions. Unlike a domain partitions, an application partition cannot store security principal objects, such as user accounts. In addition, the data in an application partition is not stored in the global catalog.
As an example of application partition, if you use a Domain Name System (DNS) that is integrated with Active Directory you have two application partitions for DNS zones -- ForestDNSZones and DomainDNSZones:
• ForestDNSZones is part of a forest. All domain controllers and DNS servers in a forest receive a replica of this partition. A forest-wide application partition stores the forest zone data.
• DomainDNSZones is unique for each domain. All domain controllers that are DNS servers in that domain receive a replica of this partition. The application partitions store the domain DNS zone in the DomainDNSZones.
Each domain has a DomainDNSZones partition, but there is only one ForestDNSZones partition. No DNS data is replicated to the global catalog server.
The below are some useful commands related to the application partitions in NTDSUTIL,
Creating and deleting application directory partitions,
#CREATE NC dc=application,dc=example,dc=com server.example.com
#CREATE NC dc=application,dc=example,dc=com null
#DELETE NC dc=application,dc=example,dc=com
Creating and deleting replicas,
#ADD NC REPLICA dc=application,dc=example,dc=com server2.example.com
#ADD NC REPLICA dc=application,dc=example,dc=com null
#REMOVE NC REPLICA dc=application,dc=example,dc=com server2.example.com
#REMOVE NC REPLICA dc=application,dc=example,dc=com null
Defining a replication schedule,
#SET NC REPLICATE NOTIFICATION DELAY dc=application,dc=example,dc=com 10 15
Displaying replica information,
#LIST NC REPLICAS dc=application,dc=example,dc=com