It is possible to gather all the information from an existing Enterprise Telephony System and then transfer it to a new cluster. In order to do this, complete these steps:
Create a Backup and Restore System (BARS) backup of the old system.
Restore the information in the new cluster.
The BARS collects the information about the user defined options, such as personal address book and fast dials. It is imperative that the version of the Cisco CallManager installed in the new cluster server is the same version that is used in the old cluster. In addition, the BARS version on the new cluster must be the same as the one that is used to perform the backup.
Note: Once the data is backed up and installed on the new server or in the new cluster, it is not possible to change the DNS name. Only the IP address can be changed.