Upgrading CICS with a running workload
The scenario uses the abilities of CICSPlex® SM to route work to any available target region, and to continue to route work, even when the maintenance point CMAS is offline. It is possible to upgrade only the CICSPlex SM component and defer the upgrade of CICS®. This scenario upgrades both at the same time.
One LPAR is upgraded first, then the other. In outline, the solution has these steps:
- Shut down, upgrade and restart the maintenance point CMAS and WUI.
- Quiesce each AOR as a workload target. When there are no longer running tasks, shut down and upgrade each AOR. Do not yet restart.
- Deregister each TOR from generic VTAM®. When no terminals are connected for that TOR and no work remains for that TOR, shut down and upgrade the TOR. Do not yet restart.
- Upgrade any remaining CMAS in the LPAR.
- Restart all CMAS.
- Restart all AORs.
- Restart all TORs.
- Repeat for the second LPAR.
Initial configuration
To streamline the diagrams, connections between LPARs are not shown.
There are two logical partitions (LPARs), with a shared CICS system definition file (CSD):
- Two CICPlex SM address spaces (CMAS), one of which is the maintenance CMAS. The CMAS on this LPAR connects to both the maintenance point CMAS and the CMAS on LPAR 2.
- Three terminal-owning regions (TORs). These regions are linked to application-owning regions (AORs) in LPAR 2.
- A WUI server.
- Ten application-owning regions (AORs). These regions are linked to terminal-owning regions (TORs) in LPAR 2.
- One CICSPlex SM address space (CMAS). This CMAS connects to the two CMAS on LPAR 1.
- Three terminal-owning regions (TORs). These regions are linked to application-owning regions (AORs) in LPAR 1.
- Ten application-owning regions (AORs). These regions are linked to terminal-owning regions (TORs) in LPAR 1.
Both sets of TORs are defined with the same z/OS Communications Server generic resource. This means that, when the regions are shut down on one LPAR, the work should transfer to the regions on the second LPAR. CICSPlex SM can pass work that comes in to a TOR to any available AOR. This means that, each TOR connects to every AOR.
Back up any data sets that you need to retain
Before you start any upgrade, you should back up any data sets that you need to retain. These data sets can include CICS system definition data sets (CSDs) and exported WUI repositories.
Upgrade the first LPAR
In this section, you upgrade one LPAR completely, then start the upgrade on the second LPAR. If you are not running a WUI server, ignore the steps that refer to it.
- Shut down the maintenance point CMAS. For more details, see Shutting down a CMAS. The CICS workload continues to run, even without the maintenance CMAS.
- Upgrade both CICS TS for z/OS and CICSPlex SM to the latest level.
- If you have a WUI, shut down the WUI server and upgrade it to the latest level.
- Start the maintenance point CMAS.
- If you have a WUI, restart the WUI. In the WUI or CICS Explorer®, you can see the CMAS and WUI at the latest level of CICS and CICSPlex SM.
- For each AOR:
- Quiesce the AOR from the workload. Check that all work that was running in that region is complete. For details, see Quiescing a target region in an active workload.
- Shut down the AOR.
- Upgrade the AOR to the latest levels of CICS and CICSPlex SM. Do not restart the AOR.
- For each TOR:
- Deregister the router as a VTAM generic resource (SET VTAM DEREGISTERED). Set close communications with VTAM (SET VTAM CLOSED), making the TOR unavailable to incoming work. For details, see Removing a TOR from a generic resource.
- When all work that is running in the region is complete, close the TOR.
- Upgrade the TOR to the latest levels of CICS and CICSPlex SM. Do not restart the TOR.
- Shut down any remaining CMAS.
- Upgrade the remaining CMAS. You can see that only the maintenance point CMAS, and WUI if present, are running in this LPAR. The TORs and AORs are upgraded but are not yet started. The second LPAR is still fully active.
- Restart the remaining CMAS. For details, see Restarting a CMAS.
- When the CMAS are active, restart each TOR.
- Restart each AOR.
Upgrade the second LPAR
When work is flowing again in the first LPAR, you can upgrade the second one.
- For each AOR:
- Quiesce the AOR from the workload. Check that all work that was running in that region completed. For details, see Quiescing a target region in an active workload.
- Shut down the AOR.
- Upgrade the AOR to the latest levels of CICS and CICSPlex SM. Do not restart the AOR.
- For each TOR:
- Deregister the router as a VTAM generic resource (SET VTAM DEREGISTERED). Set close communications with VTAM (SET VTAM CLOSED), making the TOR unavailable to incoming work. For details, see Quiescing a target region in an active workload.
- When all work that is running in the region is complete, close the TOR.
- Upgrade the TOR to the latest levels of CICS and CICSPlex SM. Do not restart the TOR.
- Upgrade the remaining CMAS.
- Restart the remaining CMAS. For details, see Restarting a CMAS.
- When the CMAS is active, restart each TOR.
- Restart each AOR.