This topic provides a procedure to convert from a Parallel Sysplex® configuration to a base sysplex configuration (a sysplex with no coupling facilities). This procedure should only be needed when it is the intent to permanently remove all coupling facilities from the configuration. By removing use of the CFRM CDSs from the sysplex (as opposed to replacing the CFRM CDS), the use of coupling facilities will be disabled and the base sysplex will remain.

An important fact to consider is that once a CFRM CDS has been added to a sysplex, the data set cannot simply be deleted. Deleting a CFRM CDS will result in a sysplex-wide wait state, even if a CFRM policy was never activated.

Also be aware that once the CFRM couple data sets have been removed, the sysplex CDS should be reformatted for the resultant base sysplex. The reformat process will eliminate any residual information about CFRM.

To remove the CFRM CDSs from a sysplex:

1. Reconfigure any sysplex function that has a dependency on the presence of a CF. The following are some examples:
   • Take DB2® out of datasharing mode.
   • Convert from global resource serialization star complex to a global resource serialization ring complex. See z/OS MVS Planning: Global Resource Serialization for more information.
   • Convert System logger to use DASD-only logging.
   • Provide XCF signaling connectivity through CTC's
   • Stop using VTAM® generic resources.
   The guidelines in Removing structures from a coupling facility for shutdown provides information on how to remove dependencies on the presence of a CF. Refer to the documentation for the specific application for more information.
2. Prevent any new coupling facility structure allocation with the SETXCF STOP,POLICY,TYPE=CFRM system command.
3. It is recommended to remove any remaining CF structures that may become persistent (that is, remain allocated without an active connector) at this point in order to minimize loss of coupling facility data. See Deleting structures for guidelines on removing structures when structure allocation is not permitted.
   The following structures do not need to be removed from the CFs:

   • BatchPipes®
   • Global Resource Serialization Lock (ISGLOCK)
   • IMS™ Fastpath MADSIOT
   • IMS OSAM and VSAM Cache
   • Enhanced Catalog Sharing
   • RACF® Database Cache
   • TCP/IP Structure for Sysplex-Wide Security Associations (SWSA)
   • TCP/IP Structure for Sysplexports
   • VSAM RLS Cache
   • WLM (IRD and Enclaves)
   • XCF Signaling
4. Create a COUPLExx SYS1.PARMLIB member that does not specify a CFRM CDS (or a CFRMPOL) and does not use XCF signaling structures (use only CTC devices for XCF signaling connectivity). Other SYS1.PARMLIB members might need to be created as well:
   • IEASYSxx - to point to the new COUPLExx and to use GRS=TRYJOIN
   • LOADxx - to point to the new IEASYSxx
   Note: It is recommended that there be alternate systems available to modify the affected system's parmlib if a modification is necessary after the affected system is shut down.
5. Shut down all images and re-IPL the systems with newly formatted sysplex couple data sets using the new SYS1.PARMLIB members. This can be accomplished in either of the following ways:
   • Shut down all images in the sysplex and reformat the current sysplex CDS(s) from a system that has DASD access to those data sets.
   • Format new sysplex couple data sets using IXCL1DSU and modify the COUPLExx sysplex CDS statements to point to the newly formatted couple data sets. Delete the old sysplex couple data sets after all systems in the sysplex are re-IPLed and are therefore no longer using the old sysplex couple data sets.

     Do not use the SETXCF command to switch to the new sysplex couple data sets.

6. The old CFRM CDSs can be deleted when XCF indicates that either CFRM is not defined to the sysplex or CFRM is not in use by any system. To determine if the CFRM CDSs can be deleted, use the DISPLAY XCF,COUPLE,TYPE=CFRM system command.