Hi Flemming,
Key question is what actions you took, if any, from the CA Gen side in conjunction with the move to Cobol 6.1 – specifically any regeneration or recompilation – neither are necessary based on the information below.
The optimisations that come with Cobol 6.x are significant but result in considerably, longer compile times, and with that, more memory to execute the optimisations and pretty much enforce batch compilation. The result is load modules optimised for execution, not size, with IBM reporting online MSU consumption of between 5%-10% and above. The variance depends on the combination of Cobol and the z-hardware you’re running. Obviously those benefits only accrue if you recompile though.
If there was no CA Gen action (no recompiles and no regenerates) then this sounds like a CA Support issue to raise so they can look at the memory management; that’s an area with significant change over the last few years.
Hope some of that helps.