Logical Components of the Exchange Store

The Exchange store has multiple interacting logical components. These components can reside on a single server, or they can be distributed across multiple servers. The following are the primary components of the Exchange store:

Storage group

A grouping of mailbox stores and public folder stores. Stores in a storage group share a single backup schedule and a single set of transaction logs. There can be up to four storage groups per server.

Mailbox store

A database for storing mailboxes in Exchange Server 2003. Mailbox stores hold data that is private to an individual and contain mailbox folders generated when a new mailbox is created for an individual. There can be up to five stores per storage group, and any number of the five stores may be mailbox stores.

Public folder tree

A group of public folders in a hierarchical structure (also known as a public folder hierarchy). One tree can have multiple public folder stores, if each public folder store is located on a separate server. These stores replicate tree information among themselves. Because several servers might hold information that belongs to a single tree, a tree belongs to an administrative group instead of to a specific server.

Each organization has one default tree named Public Folders (also known as the MAPI public folder tree) that is compatible with the Exchange Server 5.5 public folder tree and is accessible by using Microsoft Office Outlook 2003 or Microsoft Office Outlook Web Access for Exchange Server 2003. You can create new public folder trees (that are named general purpose public folder trees, also known as non-MAPI public folder trees) that users can access using Outlook Web Access. Figure 1.1 shows how Exchange Server 2003 supports multiple public folder trees on a single set of servers.

Public folder store

A database for storing public folders in Exchange Server 2003. Public folder stores hold data that is public to all users who have mailboxes and who have appropriate permissions. A public folder store must be associated with one public folder tree. There can be up to five stores per storage group, and any number of the five stores may be public folder stores.

Each server has one default public folder store (named the Public Folder Store) that supports the Public Folders tree. The following figure shows a set of public folder servers that support two public folder trees. All three servers support the Public Folders tree. Two of the servers also support a general purpose (non-MAPI) public folder tree named Accounting. Each tree has only one public folder store per server. Servers that support multiple trees have one public folder store for each tree.

Multiple public folder trees, each spread across multiple servers

Each mailbox store is associated with a default public folder store, either on the local server or another server. For each mailbox-enabled user that is supported by a particular mailbox store, the associated public folder store is the users home public folder store.

The following figure shows where these components reside in Exchange System Manager. Storage groups, mailbox stores, and public folder stores on a specific server reside under the node for the server. Public folders, displayed according to their public folder tree, reside under the Folders node.

Store information in Exchange System Manager, found under both the server's node and the Folders node

Exchange Server 2003 tracks the attributes of its components across multiple servers by storing the attributes centrally in Active Directory. Active Directory contains objects for a number of Exchange Server 2003 components, including administrative groups, storage groups, and stores. The following figure shows the objects stored in Active Directory to represent a topology consisting of one administrative group and two servers running Exchange Server 2003.

Exchange stores most configuration data in Active Directory, using Active Directory objects to represent the corresponding Exchange components