Shutting down the coupling facility

Create a plan for those cases in which it is necessary to shut down a coupling facility to apply maintenance or perform another type of reconfiguration.

About this task

For the least disruptive shutdown, move all of your structures to another coupling facility before shutting it down. See the guidelines below for handling this event. For other structures in the coupling facility, see the appropriate product documentation.

Procedure

To shut down a coupling facility, consider the following guidelines:

Prepare for the move:
- Ensure that you have enough room on the alternate coupling facility for all structures you intend to move.
- Ensure that the preference list for the group buffer pool, SCA, and lock structures contains the alternate coupling facility information.
Move simplexed structures to the new coupling facility by using the following command:
```
    SETXCF START,REBUILD,CFNAME=newcf,LOC=OTHER
```
This command rebuilds all structures that allow rebuild in the alternate coupling facility.
Deallocate duplexed structures on the original (target) coupling facility by using the following command:
```
    SETXCF STOP,REBUILD,DUPLEX,CFNAME=targetcf
```
If the CFRM policy specifies DUPLEX(ALLOWED) or DUPLEX(DISABLED), the structure goes into simplex mode.
If the CFRM policy specifies DUPLEX(ENABLED), z/OS® might try to automatically restart duplexing. If you have a third coupling facility specified in the CFRM policy, it is possible to continue duplexing during the outage of the target coupling facility. When an operator command causes the structure to drop from duplex to simplex mode, z/OS avoids automatically reduplexing the structure back into the same coupling facility from which one of the duplexed instances of the structure was just deallocated. Instead, it duplexes the structure in the third coupling facility.
Return the coupling facility to service by performing the following steps:
1. Evacuate the target coupling facility.
```
SETXCF START,REBUILD,CFNAME=cfname
```
2. Perform the maintenance operation on the target coupling facility and bring it back into the Parallel Sysplex®.
3. Repopulate the target coupling facility with the structures that were in it before the coupling facility was brought down.
```
SETXCF START,REBUILD,POPULATECF,CFNAME=cfname
```