High availability using the InfoSphere CDC for z/OS failover capability

You can set up InfoSphere® CDC for z/OS® in a failover configuration, with additional instances suspended but ready to take over active replication and administration.

In such a configuration, one InfoSphere CDC for z/OS instance is designated as the active instance. It is responsible for performing source and target subscription activities and supplying the agent for administering subscriptions by using Management Console. If additional instances are started with proper preparation, they can initialize then suspend themselves and act as the hot standby instances. Hot standby instances wait for the loss of the active instance, and when a failure is detected one of the hot standby instances resumes execution and becomes the new active instance, assuming and continuing the replication responsibilities and agent activities.

The failover capability can provide recovery of the active InfoSphere CDC for z/OS instance and continuation of its activities in any of the following situations:

• Intended termination of the active instance through operator command.
• Loss of the active instance through cancellation or abnormal termination.
• Loss of the Db2® subsystem to which the active instance is connected, either scheduled or unscheduled.
• Loss of the z/OS system on which the active instance and Db2 subsystem are running, either scheduled or unscheduled.
• Loss of the LPAR or CEC on which the active instance is running.

The failover configuration assumes that InfoSphere CDC for z/OS is connected to a Db2 subsystem that is a member of a Db2 data sharing group, and that the members of the data sharing group operate on separate z/OS instances in a sysplex.