IBM SG24-5131-00 manual Licensing Methods, Coexistence with other Applications

Note

Application start and stop scripts have to be available on the primary as well as the takeover node. They are not transferred during synchronization; so, the administrator of a cluster has to ensure that they are found in the same path location, with the same permissions and in the same state, i.e. changes have to be transferred manually.

2.5.3 Licensing Methods

Some vendors require a unique license for each processor that runs an application, which means that you must license-protect the application by incorporating processor-specific information into the application when it is installed. As a result, it is possible that even though the HACMP for AIX software processes a node failure correctly, it is unable to restart the application on the failover node because of a restriction on the number of licenses available within the cluster for that application. To avoid this problem, make sure that you have a license for each system unit in the cluster that may potentially run an application.

This can be done by “floating licenses”, where a license server is asked to grant the permission to run an application on request, as well as “node-locked licenses”, where each processor possibly running an application must have the licensing files installed and configured.

2.5.4 Coexistence with other Applications

In case of a failover, a node might have to handle several applications concurrently. This means the applications data or resources must not conflict with each other. Again, the Application Worksheets can help in deciding whether certain resources might conflict with others.

2.5.5 Critical/Non-Critical Prioritizations

Building a highly available environment for mission-critical applications also forces the need to differentiate between the priorities of a number of applications. Should a server node fail, it might be appropriate to shut down another application, which is not as highly prioritized, in favor of the takeover of the server node’s application. The applications running in a cluster have to be clearly ordered and prioritized in order to decide what to do under these circumstances.

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