The client's production CICS regions failed to start.
They found that missing prepreqs were being satisfied, but not being recognized and triggering a CICS region start.
Release : 13.0
Component : OPS/MVS
The problem was actually to be found in CA Common Services.
There was an ENQ contention, which was preventing newly started CAVARSRV tasks from synchronizing.
When CAVARSRV was brought down on this system (as it needed to be canceled), the system's attempt to synchronize with system SYS1, showed that the ENQ contention was still occurring.
The decision was made to recycle the CA Variable Service ASIDs, one at a time, on all affected LPARs, to clear the enqueue, and then execute the REQ rule, without intermixing the rebuilding of the SSMGA sysplex variables in the recycle process.