Consider multiple offline address book replicas

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2007-08-14

The Microsoft® Exchange Server Analyzer Tool queries the Exchange_PublicFolder Microsoft Windows® Management Instrumentation (WMI) class under the root\MicrosoftExchangeV2 namespace to determine the number of entries in the ReplicaList key. The number of entries represents the number of offline address book replicas that are present in each administrative group.

The Exchange Server Analyzer also queries the Active Directory® directory service to determine the number of public folder database objects that have the legacyExchangeDN attribute set. The number of objects that have this attribute set represents the number of public folder stores that exist in the organization.

If the Exchange Server Analyzer determines that only one replica of an offline address book exists in an Exchange organization that has multiple public folder stores, the Exchange Server Analyzer displays a best practice message.

For availability and performance, we recommend that you consider deploying multiple replicas of each offline address book. Sometimes, multiple offline address book replicas can increase performance and resilience. In large Exchange organizations, a single replica of an offline address book may become overloaded. In all Exchange organizations, a single replica of an offline address book is a single point of failure.

Although multiple replicas means additional replication traffic over the network, it is recommended that multiple replicas be used. At a minimum, there should be two replicas of each offline address book.

To add replicas of an offline address book to an Exchange organization

  1. Open Exchange System Manager

  2. Expand Folders, right-click Public Folders, and select View System Folders. Note   If the Folders node is not visible, expand Administrative Groups, and then expand the administrative group that contains the system folders that you want to view. Then right-click Public Folders and select View System Folders.

  3. Expand the OFFLINE ADDRESS BOOK container and then right-click the Offline Address Book you want to add a replica for by selecting Properties from the resultant drop-down list.

  4. Select the Replication tab and then clicklick Add to select the Public Store that you want to add the replica to. Click OK to finish.

  5. Repeat steps 3 and 4 for all child objects under the Offline Address Book container that you want a replica for. This repetition will make sure that all formats supported are included in the replica. that is, specifically Add the child objects OAB Version 2, OAB Version 3a, and so on.

For more information about how to manage and configure offline address books, see the following Microsoft Exchange Server TechCenter articles: