Required CF Structure changes when updating CFLEVEL and using CICS

There is no specific coupling facility parameter in CICS.

IBM recommends that you review the sizes of all your coupling facility structures using the CF Structure Sizer (CFSizer) tool before migrating to a coupling facility at a higher CFLEVEL. You should use the CFSizer Coupling Facility Sizer Tool provided by IBM. CFSizer is a web-based application that will return structure sizes based on the latest CFLEVEL for the IBM products that exploit the coupling facility.

After you read the disclaimer and accept the terms. Click on CICS then you should see the following:

• CCS Temporary Storage list structure
  

• CICS Named Counter list structure
  

• CICS Data Tables list structure
  

• CICS DFHLOG - DFHSHUNT Log structure
  

• CICS Journal/user Log structure

And, you will need to provide the requested input data. The default values have been provided for all the input data fields. These default values might or might not be reflective your environment. Modify the defaults as appropriate and click the Submit button .

After reviewing your coupling facility structures with CF Structure Sizer (CFSizer), modify your CFRM policy INITSIZE and SIZE values appropriately for the structures that changed. Then activate the modified CFRM policy before bringing the coupling facility at the new CFLEVEL into active use.

In general, IBM recommends that coupling facility structures be sized generously, erring on the side of too-large rather than too-small, because sizing structures too-small is a major factor in many different kinds of structure-related problems and outages. Be careful to re-plan so that:

• The physical coupling facility LPARs in the configuration have enough storage to accommodate the structures with their new sizes, in aggregate.

• There is enough unused space in the coupling facilities so that if a coupling facility failure occurs, the re-sized structures are still recoverable into other CF(s) in the configuration.

Most of the above recommendations can be found in section Understanding the coupling facility level (CFLEVEL) of the z/O documentation. You might also want to take a look at Coupling Facility Level (CFLevel) Considerations.