IBM Rational® license servers can be set up to run in a fault-tolerant configuration known as redundant servers.
Redundant servers are a system of three servers that work as a team to manage a single pool of floating license keys. If one of the servers goes down, the other two license servers automatically continue managing the license pool. If any two license servers no longer work, the third license server will no longer serve licenses. Two servers must operate to serve licenses to clients.
It is a common misconception that separating redundant servers across multiple sites (for example, one in the U.S., one in Europe, and one in Asia) provides maximum fault tolerance. This is not the case. Redundant servers should always be at the same site and on the same subnet.