After the Failover process is complete, monitor the central error log of the failover installation for any unexpected warnings. Warnings similar to the following will likely appear:
[08/Nov/2004:07:58:24.803 -0600] WARNING 25 CNN100 connectors-eu "Unable to obtain password of user CN=Jane Test,OU=people,DC=gt,DC=com, because the password was encoded by a previous installation of Identity Synchronization for Windows Directory Server Plugin. The password of this user cannot be synchronized at this time. Update the password of this user again in Directory Server."
These warnings occur for each password update in the Retro changelog that was made before the Directory Server Plugin was re-installed because the Primary Directory Server Plugin was configured to use a different encryption key from the failover Directory Server Plugin. Many of these password updates were likely synchronized by the primary installation before it went off line, but those that occurred after the primary installation went offline cannot be recovered. These users must change their password either in Active Directory or Directory Server to synchronize their passwords.