Resilient applications are those which have the ability to be automatically ended on one node, switched to another node, and started without requiring manual re-configuration by users. Application resiliency is based on IP address takeover and depends on the use of an application CRG.
The application must be able to recognize the loss of the Internet Protocol (IP) connection between the client and the server. During a switchover, the client application must be aware that the IP connection will be temporarily unavailable and must retry access rather than ending. During a failover, the application must recognize that the IP connection is not available and respond to the error condition by ending normally.
Application resilience enables better utilization of data resilience. To be considered resilient, an application must also provide the following:
An application CRG exit program that handles cluster events.
Automated data areas that identify information necessary to set up a resilient environment for the application and its associated data.
One or more object specifier file (OSF) that identify the objects associated with the application that must be made resilient.