Topic Last Modified: 2005-12-15

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 free/busy replicas that are present in each administrative group.

If the Exchange Server Analyzer finds that only a single free/busy replica exists in an administrative group, the Exchange Server Analyzer displays a best practice message.

It is generally recommended that more than one replica of the free/busy folder exist in each administrative group. Sometimes multiple free/busy replicas can increase performance and resilience. In large Exchange organizations, a single replica of free/busy data may become overloaded. In all Exchange organizations, a single replica of the free/busy data is a single point of failure.

It is recommended that multiple replicas be used despite the following considerations:

At a minimum, there should be one replica for every 10,000 mailboxes.

For more information about free/busy folders and publishing free/busy information, see "Working with Exchange Server 2003 Stores" (