CICSplexed and Confused? Part 2: Multi-LPAR topologies
ChrisHodgins 060000AX8A Visits (3396)
In part 1, we looked at how to connect the CICS Explorer to CICS regions on a single LPAR. In this post, we are going to extend that visibility in our CICSplex to a second LPAR. The technique for connecting a CICSPlex SM environment between two LPARs is the same regardless of the number of LPARs you have. However we will see in part 3 and 4 additional optimisations and considerations for scaling critical environments.
Our starting example is the final environment from part 1 plus an additional LPAR B with 3 CICS regions.
The first goal is to bring the CICS regions on LPAR B under control of CICSPlex SM and into our CICSplex MYPLEX. As in part 1, we do this by starting a CMAS on the LPAR. You'll need a CMAS in each LPAR that you want the CICS Explorer to be able to reach. When we initialised the CICSPlex SM Data Repository (the CICSPlex SM equivalent to the CSD) for the CMAS on LPAR A, the CICSplex definition and the WUI region definition was created for the CICSplex. However, when we initialise the the Data Repository (DREP) for the CMAS on LPAR B, we specifically do not want to do this. Doing so, would create a new CICSplex of the same name owned by the CMAS on LPAR B. As we created the CICSplex for the CMAS on LPAR A in part 1, that CMAS is the CICSplex owner, otherwise known as the Maintanence Point (MP) CMAS. Other CMAS that are required for connectivity are only assigned to manage the CICSplex.
The CMAS on LPAR B is now running. Again as in part 1, to establish connectivity between the CMAS and CICS regions, the CICS regions must be added to the CICSplex and converted into MAS regions. The CICS regions are added to the CICSplex through the CICS Explorer as in part 1.
Although the CICS regions are now defined to the CICSplex, connectivity between the CICS Explorer and the CICS regions hasn't been established yet. The CMAS on LPAR B hasn't been assigned to manage the CICSplex and even if it was there is no connectivity between the two CMAS. This connectivity is set up by creating a CMAS to CMAS connection definition for each CMAS to allow it to connect to the other. You can specify MRO to connect between LPAR on the same Sysplex or LU6.2 to connect to a CMAS in a different Sysplex. This will allow both CMAS to communicate and once this is done, assigning the CMAS to manage the CICSplex will allow the CICS regions on LPAR B to connect. The moment they connect they will appear in the CICS Explorer attached to the WUI on LPAR A.
To summarise the steps briefly.
The IBM Knowledge Center for CICS Transaction Server V5.1 has more detailed information on this topic:
As suggested above, the techniques applied here can be used to connect large numbers of LPARs together but there are some additional improvements we can make, especially if we need to scale this out to many LPARs. In the next post, we will take another look at the topology, discuss the limitations around upgrades and make an improvement, then in part four we will look at CMAS to CMAS connectivity and discuss the topology again from a high availability stand-point.