Upgrading or replacing a coupling facility

This topic has a procedure for upgrading/replacing a coupling facility (CF) when all CF structures can be removed from the CF and the hardware identification of the CF will change. If the CF hardware identification will not change, see Shutting down a coupling facility for maintenance. 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 coupling facility), then follow the instructions in Upgrading or replacing all coupling facilities.

Take the following actions before upgrading/replacing a CF:

Define a new CFRM policy that replaces the CF hardware identification information with the information for the new CF. Use a name for the new CFRM policy that is different from the name of the active CFRM policy so that the original policy can be restored easily if a problem occurs. See Planning a coupling facility policy for more information.
Note that the same CF name can be used for the new CF. If a different name is used for the new CF, structure preference lists will also need to be updated.
CHPIDs being used for connectivity between all systems and the CF should be recorded at this point. The CHPIDs used for connectivity between a system and a CF can be obtained using the ROUTE *ALL,DISPLAY CF,CFNAME=cfname system command.
Information about CF connectivity to systems and CF characteristics is returned in message IXL150I. Record the following information that uniquely identifies the CF to each system:
- NODE DESCRIPTOR (type.mfg.plant.sequence)
- PARTITION
- CPCID
- CHPID's (listed under SENDER PATH heading)
Activate the new CFRM policy with the SETXCF START,POLICY,TYPE=CFRM,POLNAME=polname2 system command.
Assuming at least one structure is allocated in the CF, the policy changes to replace the CF definition will become pending. Replacement or pending deletion of the CF definition from the CFRM active policy can be verified with the DISPLAY XCF,CF,CFNAME=cfname system command.
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.
Unless REALLOCATE is used, any change to the preference list of a structure that was not allocated in the CF being removed might remain pending.

Once all structures are removed from the CF, the CF definition in the CFRM active policy will be replaced with the definition that uses the new hardware identification. Replacement of the CF definition in the active policy should be verified with the DISPLAY XCF,CF,CFNAME=cfname system command.
Using the CHPIDs from a preceding step, on all systems, place all paths to the CF offline with the CONFIG CHP(chpxx,chpyy...),OFFLINE system commands:
Verify the CHPIDs on all systems with the DISPLAY M=CHP(chpxx,chpyy...) system commands.
SHUTDOWN the old CF.

CF upgrade/replacement can be performed when preceding actions are complete.

The CF upgrade/replacement may involve hardware changes or changes to the I/O configuration. See z/OS HCD Planning and z/OS HCD User's Guide for more information on adding and removing coupling facilities from the I/O configuration.

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. Changes to CF elements can be verified on all systems with the system command(s)

DISPLAY CF
DISPLAY M=CHP(chpxx,chpyy...)

Use the following procedure to bring the upgraded/replacement CF into use when upgrade/replacement is complete:

Ensure CF CHPIDs are online. Use the CONFIGURE CHPID ONLINE command on a CF to configure a CF CHPID online.
Verify CHPIDs in use with the following commands:
```
DISPLAY CHPIDS  
DISPLAY RESOURCES 
```
See PR/SM™ Planning Guide for more information on coupling facility control code commands.
Place all paths to the CF online with the CONFIG CHP(chpxx,chpyy...),ONLINE system command.
Verify the availability of the CF on all systems with the following system command:
```
DISPLAY XCF,CF,CFNAME=cfname
DISPLAY M=CHP(chpxx,chpyy...)
DISPLAY CF    
```
The CF will not contain any structures. 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 CFs after CF maintenance is complete.