Benefits of implementing CICS in a Parallel Sysplex

Information about the benefits to be gained from implementing CICS in a Parallel Sysplex®.

Enterprises have traditionally run multiple CICS® regions, with separate regions dedicated to specific responsibilities (terminal owning region, application owning region, queue owning region, and so on). Extending CICS to maximize availability in a Parallel Sysplex is the next logical step.

Among the benefits a Parallel Sysplex can potentially deliver in a CICS environment:
  • High availability and continuous operation.
    If there are multiple regions to deliver a CICS function, it should be possible to stop any of those regions and still deliver the service to the user, provided at least one of those regions is still available. If a CICS region experiences a planned or unplanned outage, all the work that the region would otherwise process should automatically get routed to one of the other regions. This would provide the following benefits:
    • Minimize the number and impact of unplanned outages.
    • Minimize the number and impact of planned outages.
    • Maximize the availability of CICS applications.
    • Ensure that CICS application meets or exceeds the business SLA requirements.
  • Scalability.

    The concept of Parallel Sysplex is that any work should be able to run on any member of the sysplex. For CICS, this means that if you require extra CICS capacity, it should be possible to quickly and easily clone another CICS region, add it to any system in the sysplex, and work should automatically start flowing to that region.

  • Flexibility.

    If you want to reduce the number of CICS regions, it should be possible to stop a region, and all the work that was running in that region is now routed to one of the other remaining regions.

    You can also move CICS regions from one system in the sysplex to another (for example, if one central processing complex (CPC) is upgraded to add more capacity). By easily being able to move regions, you can exploit the additional capacity on the upgraded CPC and free up capacity on the CPCs from which the regions are moved.

  • Performance.

    Whether the CICSplex spans multiple systems in the sysplex or not, it should be possible to optimize performance by routing CICS transactions to the CICS region that can deliver the best response time to the user.

  • Simplified systems management and single system view.

    CICSPlex® SM can manage multiple CICS regions, not just in a single z/OS® image, but across a Parallel Sysplex.

To fully achieve these benefits, changes to the applications might be required. For more information about making your applications Parallel Sysplex ready, see Planning for migrating CICS to a Parallel Sysplex.