Datasheet

10 Chapter 1
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Preparing for the Exchange Installation
Active Directory Partitions, Masters, and Replication
The information contained within Active Directory is not all stored in a single location, or
partition in this case. Actually, five Active Directory partitions contain different pieces of
information about the Active Directory forest and domains. Because each partition type
contains different information, the domain controllers to which each partition type is repli-
cated within the forest are also different. We’ll briefly cover these directory partitions in the
following sections.
Domain Partition
The domain partition contains all the objects that you as an administrator are used to working
with on a daily basis. These objects include items such as user accounts, computer accounts,
and groups. The contents of the domain partition thus are specific to each individual domain
within a forest and therefore are replicated only to the domain controllers in that specific
domain.
Configuration Partition
The configuration partition contains all the configuration information about the forest,
including information about Active Directory and AD-integrated applications such as
Exchange Server. As such, the configuration partition is replicated to every domain control-
ler in the entire forest. Applications benefit from storing their configuration data in the con-
figuration partition because no additional work or configuration is needed to ensure that
configuration information is available forest-wide.
Schema Partition
The schema partition, true to its name, is the housing location for the information that
defines what objects exist within that Active Directory forest. Each object also has mul-
tiple attributes that can be configured, and thus they are also defined in the schema. The
schema partition, being so critical to Active Directory, is also replicated to every domain
controller in the forest. Unlike other data in Active Directory, only one copy of the schema
partition is writable; that is to say that only one domain controller can make changes to
the schema. This special domain controller is known as the schema master. We’ll discuss
the “roles” that domain controllers hold, including that of the schema master, later in this
chapter.
Application Partition
Application partitions were introduced in Windows Server 2003 and were designed for hold-
ing data that is specific to an application. By default, no application partitions are created
in a fresh installation of Active Directory; however, some are usually created to store Active
Directory–integrated DNS zones. Application partitions are not limited to being replicated to
only a single domain or the entire forest—replication can occur with any domain controller
in the forest, spanning multiple domains.