Prerequisites for failing over to the Business Continuance site

For a planned failover to a Business Continuance server, ensure that you have a valid disaster recovery plan, perform backup of all Storage Groups, and ensure that the Exchange server is offline at the production site.

For a planned failover, you must first meet the following conditions:

Create a valid disaster recovery plan.
Perform a complete backup of all Storage Groups, using Update SnapMirror after backup option so that you do not lose any data.
Ensure that the Exchange server is offline at the production site after you complete the backup operation.
Convert the DNS running on the disaster recovery site to primary and ensure that it is write-enabled to execute the Business Continuance plan successfully.
Ensure that there are no non-Exchange LUNs in the Exchange volumes.
If you configure non-Exchange LUNs in Exchange volumes, the Business Continuance recovery operation recovers only Exchange and SnapManager SnapInfo LUNs.
For standalone Exchange configurations involving "storage only failover", you must manually dismount the storage groups in the Business Continuance plan, prior to executing the planned failover of the Business Continuance Plan.
If necessary, reinstall the passive mailbox server role to a site that was the failover destination of an earlier operation. If you get an error trying to fail over to that site again:
Clustered Mailbox Server Performing Microsoft Exchange Server Prerequisite Check Configuring Microsoft Exchange Server ... FAILED Setup previously failed while performing the action "Install". You cannot resume setup by performing the action "DisasterRecovery". The Exchange Server Setup operation did not complete. For more information, visit http://support.microsoft.com and enter the Error ID. Exchange Server setup encountered an error. Setup.com completed with Return code: [1]
1. Remove all of the registry keys except for ConfiguredVersion and UnpackedVersion from the following registry path (in which <ServerRole> is the Exchange role installed on your server):
  HKLM\Software\Microsoft\Exchange\v8.0\<ServerRole>
2. Perform this operation for all roles on your server.
3. Reinstall the passive mailbox server role on that site.