Configuring a processor and a coupling facility

Coupling facility channels provide the connectivity between a coupling facility and the CPCs or LPARs directly attached to it. Coupling facility links (ISC-3 and IFB links) are defined to the server running the z/OS operating system and to the LPAR running the coupling facility.

PR/SM™ Planning Guide describes the different type of coupling facility channels, including peer mode links, which can provide both sender and receiver capability on the same link by being configured as an unshared channel path to a single coupling facility and at the same time as a shared channel path among several sender LPARs. CF-to-CF links allow a coupling facility sender channel to communicate with another coupling facility, a function that is required for system-managed duplexing rebuild.

PR/SM Planning Guide also provides guidance for configuring coupling facility links in a sysplex. Just as a coupling facility cannot be shared among sysplexes, there are configuration restrictions for coupling facility links as well. Links from a coupling facility owned by a sysplex should not be connected to systems outside the sysplex. If a configuration does contain CF links that are connected to systems both in and outside the owning sysplex, the CF links to systems outside the sysplex must be configured offline before the coupling facility is used by systems in that sysplex.

Both the coupling facility LPAR and the coupling facility channel paths must be defined to the I/O configuration data set (IOCDS). HCD provides the interface to accomplish these definitions and also automatically supplies the required channel control unit and I/O device definitions for the coupling facility channels.

To determine the logical partition identifier to specify in the CFRM policy, following these rules:

If the coupling facility is defined on a z990, z890, or later processor, then the PARTITION value must match the partition ID associated on the activation profile for the CF image on the support element or hardware master console.
If the coupling facility is defined on a pre-z990 or pre-z890 or earlier processor, then the PARTITION value must match the partition number specified by HCD/IOCP in the IOCDS for that partition and can be in the range of 01-0F.
When moving a coupling facility to a different PARTITION, remember to update the CFRM policy.

See CFRM parameters for administrative data utility for information about defining a CFRM policy.

See z/OS HCD Planning for information about defining a coupling facility with HCD.

See PR/SM Planning Guide for information about defining a coupling facility on a z900 processor using the Customize/Delete Activation Profiles task.