Hi,
I would like to know what your main concern is with having a single HA components for the system in the same datacenter.
In CWMS 2.5 we support dual-data center deployments where you have two CWMS solutions (without HA) deployed in two different datacenters, and then they are joined into a single solution over WAN. http://www.cisco.com/c/en/us/td/docs/collaboration/CWMS/2_5/Administration_Guide/Administration_Guide/Administration_Guide_chapter_010011.html
However, if you want to have a full system with HA in one datacenter and then have another "Cold Standby" system in the other datacenter, you should deploy this "cold standby" system to be identical to your original system (same setup), and then in case of a failure, you should power off the original system and power on the "cold standby" system, connect it to NFS storage of the original system and restore from backup. Finally, at that time, you will have to request rehosting of the licenses for this new system. You don't need to purchase additional licenses for this, but when you plan to use this "cold standby" system, you will have to rehost the licenses using the same PAK but License Request from this new system. Keep in mind that you shouldn't ask for rehosting of licenses ahead of time, because if you rehost the license on one system, you won't be able to get any incremental licenses for the old system and other way around.
I hope this helps.
-Dejan
