It will take more information than I can provide here to fully plan out a new CICSPlex environment, but I will hit on some of the primary things that should be considered, and how I decided to lay out the CICSPlexes in our shop.
At the top of the list of things to be considered in laying out a CICSPlex are what CICS regions are to be part of a CICSPlex, and your goals in implementing CICSPlex. You may very well want all of your regions in a CICSPlex, but in our shop I found that there were a couple of specialty test regions that I may put into a separate CICSPlex later, but for now they just are not part of any CICSPlex. Your goals in implementing CICSPlex will determine how CICS regions are grouped into one or more CICSPlexes. For example, if you are not planning to use WLM to manage the workloads between CICS’s, you can pretty much group your CICS’s however you’d like. If you are planning to use WLM to balance workloads between regions, you would need to ensure that all target regions are in the same CICSPlex as corresponding routing regions. If you use or plan to use BTS, then all regions that are part of a BTS-set will need to be in the same CICSPlex.
IBM suggests that if you have no WLM or BTS restrictions, you should consider putting all of your regions into a single CICSPlex. This is certainly a simple way to go. One of our primary goals in implementing CICSPlex was to take advantage of its monitoring capabilities, and we wanted to give our application programmers the ability to perform tasks such as purging tasks in our test and development regions but not in production regions. So it made sense to us to define two CICSPlexes – one for production regions, and one for test/development regions. Besides making it simpler to provide different security to each, it also gives us a test environment in which we can apply maintenance first, before rolling it into production. If you are a (or the) CICS sysprog in your shop, you will know about the little things that will help decide the best way to plan out the number of CICSPlexes and which regions will participate.
Read through IBM’s CICSPlex Concepts and Planning manual, and you will likely have a good idea of how to plan out which CICS’s should be part of a CICSPlex, and how many CICSPlex’s you will need.
Next time, we’ll jump into setting up a CMAS – the controlling region in a CICSPlex.
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