Error Message

"Already in use"

Public Folders are not covered by DAG, public folders are setup the same way in previous version of Exchange with replicas.

Note:
The “temporary” SCR capability for Public folder databases offered in Exchange 2007 has been removed in Exchange 2010. So in previous versions clients connected directly to the public folder server (no CAS proxying).
Public Folder access will still go direct and not via the CAS.

New items are unable to be archived while in the failover state.  Retrieval will work as expected. 

Recommendation:
Use one server as a primary and let it always be the active one, and revert back to that server once the situation that caused the failover is resolved. This means the archive targets for the public folder will not need to be switched.

The important thing to make sure is the content (replica) is from the targeted public folder server and that the system mailbox Public folder DB is one containing the content (and doesn’t need to generate a referral request). It means that just ensure the Server/Mailbox/PF database/Replica are in the same place i.e. ensure that the replica actually contains the data to archive and does not need to perform any referral to other PF stores.