Dedicated Public and Private Servers vs. Multipurpose Servers

You can centralize responsibilities among Microsoft Exchange Server computers by configuring all the Microsoft Exchange Server computers to be either public or private servers. A dedicated private server has a private information store (dedicated to private mail storage and user mail), but no public information store. A dedicated public-folder server stores and processes requests for information about the public folder, such as its hierarchy and contents. A dedicated public-folder server does not have a private information store.

Having a dedicated public-folder server means that other servers can concentrate their processing efforts on private message storage and user message transfers. Dedicated public-folder servers still participate in directory replication. Consider using a dedicated public-folder server if there is a large amount of data in a public folder system or if frequent and timely access to public folders is critical.

Each Microsoft Outlook client obtains public folder hierarchy information from a public information store. If you have dedicated public servers, those servers respond to the clients for both folder hierarchy information and content data. As a result, it is possible for the servers to become overwhelmed with traffic. In this case, maintaining a public information store on each server enables clients to retrieve the folder hierarchy information from their local server while connecting to the public server for content data. In this way, requests for various types of data can be distributed for best performance.

If you have a large site with more than 20 servers, a dedicated private server can be your best option. In this case, your system benefits from not replicating the public folder hierarchy to every server, especially if public folders are created and deleted frequently.

Configuring separate public and private servers allows you to plan the hardware needs for a particular computer according to its role. In other words, if you know that a public server will be heavily used, you can use a higher-speed processor, more random access memory (RAM), and so on.

You can assign different tasks to different servers.

    To assign different responsibilities to public servers and private servers

1. Move all of the public folders to the public servers using the Replicas property page on the public folder or the Instances property page for the target public information store.
2. For each private server, configure the private information store so that the public folder server is the appropriate public server. To do this, use the General property page for the private information store server object.

   This step ensures that all top-level public folders that are created in the future are located on the new public servers.

3. Use the Microsoft Exchange Server Administrator program to remove the private information store from the public servers and the public information store from the private servers. To do this, delete the private information store object from the server container in the Administrator program. Also, move mailboxes off of the public-only servers.

Separating public and private servers also concentrates the flow of public folder traffic. In this way, replication of the public folder hierarchy and contents takes place only between the public servers and does not have an impact on the private servers.