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In a multiple-tenant hosting environment such as Microsoft Hosted Messaging and Collaboration (HMC), each hosted tenant is configured to use only one Offline Address Book (OAB). Therefore, you must generate an OAB for each tenant on HMC 4.5 or on HMC 4.0. However, new OABs are not generated or Public Folder Hierarchy replication may not be successful. When this behavior occurs, the following events are logged:
Event Type: Error Event Source: MSExchangeIS Event Category: General Event ID: 9669 Description: Failed to create a new replica identifier for database " <Storage Group> / <Public Folder Store> " because the number of replica identifiers reached the quota limit (<Number>). User attempting to create the replica identifier: " <Replid> "
This problem occurs because the maximum number of OABs that can exist in HMC is limited by the architecture of public folders. Specifically, the Replication ID limit is 32,768. Additionally, each OAB that you create consumes one Replication ID in the public folder hierarchy. Therefore, when you exhaust all the Replication IDs in the database, new OABs are not generated, or public folder hierarchy replication may not be successful.
When you exhaust all the Replication IDs, you must reduce the number of OABs to less than 20,000. Additionally, all the public store databases must be rebuilt. To do this, follow these steps:
Reduce the number of OABs to fewer than 20,000.
If you have non-OAB public folder content, make arrangements to move it to a non-Exchange data store such as a .pst file.
Unmount all the Public Store databases in the organization. Note If any Public Store databases remain online, the whole process will fail.
Delete the physical files that are associated with the Public Store databases.
Mount the public store databases to re-create the database files.
Restore the public folder content from External Store.
Update the existing OABs, and then rebuild them by using Exchange Administrative Tools.
The problem is not specific to HMC 4.5 or to HMC 4.0. However, HMC customers are more likely to create many OABs. This problem also occurs when you create more than 32,768 Public Folder-based OABs in any version of Exchange Server.
You may also experience the Replication ID problem on an Exchange Server 2007 server. For more information about this problem, visit the following Microsoft Web site: