Levels of application resiliency
Application resiliency can be customized to the level of resiliency that your business requires using the features of the IBM® i clustering framework.
Recovery Time Objective (RTO) for your business plays directly into the level of application resiliency that is needed. As it is defined in the Components of High Availability topic, there are different levels of application resiliency. These application resiliency levels range from no application recovery, where a system operator must start the application manually, to uninterrupted service, where the user may not even know that an outage even happened. Your business requirements for the application to be available to the user after a failure sets the requirements for how much automation the resilient application must recover in the event of a system failure.
The IBM i clustering framework gives the ability to automate the application recovery for different types of failures. The amount of automation possible depends on the amount of coding to automate manual procedures and the type of application your business is using. To maximize application resiliency, all manual switchover/failover steps must be automated with exit programs, and the application must be a client-server type application where the application availability is separated from the application data availability.