Enabling Continuous Availability of Couple Data Sets

Couple data sets (CDSs) contain important information about how to manage certain aspects of your sysplex. For example, the SFM CDS (sysplex failure management couple data set) defines how the system manages system and signalling connectivity failures and PR/SM (Processor Resource/Systems Manager) reconfiguration actions.

The following couple data sets are particularly important for the functioning of your Parallel Sysplex:

  • The SYSPLEX couple data set, which defines the systems and the XCF groups of the sysplex
  • The CFRM couple data set, which defines the coupling facilities and structures of the sysplex

It is recommended that you define alternate couple data sets for all couple data sets in your sysplex. These alternate couple data sets serve as backups when the primary CDS fails.

With the customization dialog you can specify a series of spare volumes for every CDS type, for example, SYSPLEX, ARM, CFRM. The first volume in the series is used to create an alternative CDS if one of the primary alternate CDSs fails.

In the customization dialog you define the potential alternate couple data sets using the Group entry type. Select a sysplex group, then select its policy item SYSPLEX (define sysplex policy) from the panel Policy Selection.

The Sysplex Policy Definition panel is displayed if you select policy item SYSPLEX from the Policy Selection panel for sysplex groups.

For a description of this panel refer to the online help or the section "More About Policy Item SYSPLEX" in IBM Z® System Automation Defining Automation Policy .