Does a Client have to Purchase another set of Licenses if they want to Run Workloads for Disaster Recovery?

The Answer is No! Provided that they jump through a large set of hurdles...

Disaster Recovery Rights

For each instance of eligible server software you run in a physical or virtual OSE on a licensed server, you may temporarily run a backup instance in a physical or virtual OSE on a server dedicated to disaster recovery. The license terms for the software and the following limitations apply to your use of software on a disaster recovery server.

The OSE on the disaster recovery server can run only during the following exception periods:

• For brief periods of disaster recovery testing within one week every 90 days
• During a disaster, while the production server being recovered is down
• Around the time of a disaster, for a brief period, to assist in the transfer between the primary production server and the disaster recovery server

In order to use the software under disaster recovery rights, you must comply with the following terms:

• The OSE on the disaster recovery server must not be running at any other times except as above.
• The OSE on the disaster recovery server may not be in the same cluster as the production server.
• Windows Server license is not required for the disaster recovery server if the following conditions are met:
• The Hyper-V role within Windows Server is used to replicate virtual OSEs from the production server at a primary site to a disaster recovery server.
• The disaster recovery server may be used only to run hardware virtualization software, such as Hyper-V, provide hardware virtualization services, run software agents to manage the hardware virtualization software, serve as a destination for replication, receive replicated virtual OSEs, test failover, and await failover of the virtual OSEs.
• Run disaster recovery workloads as described above.
• The disaster recovery server may not be used as a production server.
• Use of the software in the OSE on the disaster recovery server should comply with the license terms for the software.
• Once the disaster recovery process is complete and the production server is recovered, the OSE on the disaster recovery server must not be running at any other times except those times allowed here.
• Maintain Software Assurance coverage for all CALs, External Connector licenses and Server Management Licenses under which you access your licensed software running on the disaster recovery server and manage the OSEs in which that software runs.
• Your right to run the backup instances ends when your Software Assurance coverage ends.

These rules come from the Microsoft product use rights guide page 70 (will change).

To see the Full Guide to Microsoft's Product Use Rights, Click Here: http://www.microsoft.com/licensing/products/products.aspx