This topic provides a procedure for shutting down a coupling facility (CF) for maintenance when all CF structures can be removed from the CF and hardware identification information for the named CF is not changing. If not all structures can be removed from the CF (for example, the Parallel Sysplex® configuration is a global resource serialization star complex with a single usable CF), then CF maintenance procedures should be performed while all systems are inactive. If the CF hardware identification will change, see Upgrading or replacing a coupling facility instead.

The procedures in this topic require that all systems are at z/OS® V1R9.0 or above in order to exploit maintenance mode. If this requirement is not met, the CF must be deleted and then re-added. See Removing a coupling facility from the configuration.

The procedures in this topic require that the CF contains no structures in transition or pending deallocation. If the CF contains a structure in transition or pending deallocation, connectivity to the CF should be restored. If connectivity to the CF cannot be restored, the CF must be deleted and then re-added. See Removing a coupling facility from the configuration. Structures that are in transition or pending deallocation are marked as (TRN) or (PND) in the output of the system command DISPLAY XCF,CF,CFNAME=cfname.

To exploit maintenance mode for shutting down a CF, consider the following procedure:

1. Prevent systems from allocating any structures in the CF by placing the CF in maintenance mode using the SETXCF START,MAINTMODE,CFNAME=cfname command.

   Verify the denial of structure allocation due to maintenance mode with the DISPLAY XCF,CF,CFNAME=cfname command.

2. Remove all structures from the CF. See Removing structures from a coupling facility for shutdown for guidelines on removing all structures from a CF that is in maintenance mode.

   Verify the removal of all structures from the CF with the DISPLAY XCF,CF,CFNAME=cfname command.

3. On all systems, place all paths to the CF offline with the VARY PATH(cfname,chpxx,cfname,chpyy...),OFFLINE,UNCOND command.

   The logical removal of all system connections to the CF should be verified with the following system commands:

   DISPLAY XCF,CF,CFNAME=cfname
   ROUTE *ALL,DISPLAY CF,CFNAME=cfname  

4. SHUTDOWN the CF.

CF maintenance can be performed when preceding actions are complete.

If making changes to CF elements (CF control units or CF channel paths) in the I/O configuration, ensure that SOFT=VALIDATE is specified on the ACTIVATE system command. SOFT=VALIDATE is a requirement in all N-1 partitions when changes to CF elements are made.

Use the following procedure to bring the CF back into use after maintenance is complete:

1. When CF maintenance is complete, on all systems, place all paths to the CF online with the VARY PATH(cfname,chpxx,cfname,chpyy...),ONLINE command.
   Verify the system connections to the CF with the following system commands:

   DISPLAY XCF,CF,CFNAME=cfname
   ROUTE *ALL,DISPLAY CF,CFNAME=cfname 

2. Take the CF out of maintenance mode to permit structure allocation with the SETXCF STOP,MAINTMODE,CFNAME=cfname command.

   Verify the permission to allocate structures in the CF can be verified with the DISPLAY XCF,CF,CFNAME=cfname command.

3. See "Using REALLOCATE or POPULATECF to relocate coupling facility structures" in Managing coupling facility resources for a description of how to move structures to their most preferred CF(s) after CF maintenance is complete.