Configuring Public Folder Stores

A public folder store holds information associated with a particular public folder tree, such as how the tree is structured and what folders the tree contains. It also holds public folder content.

Each new Exchange server has one default public folder store (named Public Folder Store). This store supports the Exchange default public folder tree, which is named Public Folders in Exchange System Manager and All Public Folders in Outlook, and is sometimes named the MAPI public folder tree. Users can access this tree with MAPI-based clients, such as Outlook, and with HTTP-based clients, such as Microsoft Outlook® Web Access. There is only one Public Folders tree in each Exchange organization, and all the default public folder stores replicate this tree and its content among themselves.

You can create new public folder trees, named general-purpose public folder trees, (also named non-MAPI public folder trees). Users can access folders in general-purpose trees using Web-based clients, NNTP clients, and standard Windows applications in which the folders are mapped as network drives using WebDAV. Use general-purpose public folder trees as file repositories for departments, groups, or projects. For more information, see Configuring a New Public Folder Tree and Public Folder Store.

If you create a new public folder tree, you can then create an additional public folder store to support that tree. Each server can only have one store for each public folder tree. In other words, the server can have multiple public folder stores if each store supports a different public folder tree. For more information, see Creating a New Public Folder Store for an Existing Public Folder Tree.

The following figure shows an example of a set of public folder servers that support multiple trees:

• Each server has a Public Folder Store, which supports the Public Folders tree.

• Two servers also support a second public folder tree. These servers run one public folder store per tree.

Multiple public folder trees, each spread across multiple servers

If you try to create a public folder store without an available public folder tree, you receive the following error message:

All the public folder trees already have an associated public store on the server. You must create a new public folder tree before creating this new public folder store.

The following figure shows where to find public folder store information in Exchange System Manager.

Public folder store information in Exchange System Manager

This section describes the following:

• Functions of the Public Folder Store, especially when it is associated with a mailbox store.

• How to add a public folder store when you work with an existing public folder tree.

• How to configure a new public folder tree and public folder store.

• How to configure the default public folder storage limits:

  • Maximum size of public folders and of individual items in the folders.

  • Length of time deleted items are retained.

  • Age limits for items in public folders.

• How to control public folder store settings with system policies.

• Interfaces to use for monitoring public folder store activity.

For information about configuring the store's options for the default public folder replication interval, see "Controlling Exchange Server 2003 Public Folder Replication" in Working with the Exchange Server 2003 Store.