The following scenario illustrates how XCF processes COUPLExx data set definitions for systems that are joining the sysplex. Consider that the sysplex has defined four sysplex couple data sets: SYS1.CDS01, SYS1.CDS02, SYS1.CDS03, and SYS1.CDS04.

1. System SYSA initializes the sysplex with the following COUPLExx values:
   • PCOUPLE=SYS1.CDS01
   • ACOUPLE=SYS1.CDS02

   The active primary sysplex couple data set for the sysplex is SYS1.CDS01. The alternate is SYS1.CDS02.

2. System SYSB tries to join the sysplex with the following COUPLExx values:
   • PCOUPLE=SYS1.CDS01
   • ACOUPLE=SYS1.CDS02

   The COUPLExx definitions match those that are in effect for the sysplex. XCF allows SYSB to join the sysplex.

3. The operator issues SETXCF COUPLE,PSWITCH to make the alternate sysplex couple data set SYS1.CDS02 the new primary sysplex couple data set.

   The active primary sysplex couple data set for the sysplex is now SYS1.CDS02. There is no alternate defined for the sysplex.

4. The operator issues the SETXCF COUPLE,ACOUPLE command to define SYS1.CDS03 as the new alternate sysplex couple data set for the sysplex.

   The active primary sysplex couple data set for the sysplex is SYS1.CDS02. The alternate is SYS1.CDS03.

5. System SYSC tries to join the sysplex with the following COUPLExx values
   • PCOUPLE=SYS1.CDS01
   • ACOUPLE=SYS1.CDS02

   The COUPLExx definitions do not match those that are in effect for the sysplex. XCF issues messages to indicate the values for the sysplex couple data sets in effect for the sysplex. XCF allows SYSC to join because at least one of its sysplex couple data sets was previously defined for the sysplex when SYSA initialized the sysplex.

6. The operator issues SETXCF COUPLE,PSWITCH to make the alternate XCF data set SYS1.CDS03 the new primary sysplex couple data set.

   The active primary sysplex couple data set for the sysplex is now SYS1.CDS03. There is no alternate defined.

7. System SYSD tries to join the sysplex with the following COUPLExx values
   • PCOUPLE=SYS1.CDS01
   • ACOUPLE=SYS1.CDS02

   XCF definitions do not match those that are in effect for the sysplex. XCF issues messages to indicate the values for the sysplex couple data sets in the sysplex. XCF allows SYSD to join because at least one of its XCF couple data sets was previously defined for the sysplex when SYSA initialized the sysplex.

8. The operator issues SETXCF COUPLE,ACOUPLE to define SYS1.CDS04 as the new alternate sysplex couple data set.

   The active primary sysplex couple data set for the sysplex is now SYS1.CDS03. The alternate is now SYS1.CDS04.

9. The system programmer updates COUPLExx for SYSA, SYSB, SYSC, and SYSD to reflect the current PCOUPLE and ACOUPLE values.
10. The system programmer deletes sysplex couple data sets SYS1.CDS01 and SYS1.CDS02.