Configuring redundant license servers on UNIX

You can configure the License Key Server in a fault-tolerant configuration, which is known as redundant servers.

Use a redundant environment of either all Windows servers or all UNIX 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. This type of redundant configuration requires that a minimum of two license servers run always. If two license servers no longer work, the third license server does not serve licenses. Two servers must operate to serve licenses to clients.

It is a good practice to have a homogeneous redundant server set up even though, heterogeneous environments are supported. In a homogeneous redundant server setup, all servers are installed on the same operating system. For example, you might have two license servers that are installed on Solaris and one installed on HP-UX.

To configure redundant license servers:
  1. Install the License Key Server on three computers. See Installing the license server on UNIX.
  2. Import a license file that you receive from IBM on each license server.
  3. Start the license servers. The sequence is not important, but start the servers soon after one another. For instructions, see Starting and stopping the UNIX license server.
  4. Give client users the Primary, Secondary, and Tertiary (Backup) license server hostnames in the order that you requested the hostnames in the IBM License Key Center. Users must enter the host names in their License Key Administrator.
  5. When shutting down a three-server redundant license server system, there is a one-minute delay before the servers shut down. lmdown shuts down all three license server systems of a set of redundant license server systems. If you need to shut down one of a set of redundant license server systems (not recommended because you are left with two points of failure), you must kill both the lmgrd and vendor daemon processes on that license server machine.

You have purchased 25 floating licenses and plan to configure a redundant server configuration on three UNIX computers. You request permanent keys for the redundant servers by using the IBM License Key Center. You install the License Key Server on each of the redundant servers; servers A, B, and C. When you receive the license file of 25 permanent floating keys, you install the license file on each server.

The three servers work as a team to manage all 25 floating licenses. When you have 20 license keys that are checked out to your users and server A fails, servers B and C continue to manage the 25 licenses.
Important: You must locate redundant servers at the same site and on the same subnet. Separating redundant servers among multiple sites (for example, one in the US, one in Europe, and one in Asia) does not provide maximum fault tolerance.