2. PERFORMANCE REPORTING ANALYSIS › 2.8 Sysplex Analysis › 2.8.2 Usage Guidelines › 2.8.2.2 Tracking Coupling Facility Hardware

2.8.2.2 Tracking Coupling Facility Hardware

It should come as no surprise that as more MVS systems
participate in the data sharing activities of a parallel
sysplex, the greater is the need for increased coupling
facility capacity and coupling facility channel connectivity.

As you install or add coupling facility channels between MVS
systems and coupling facilities, you must consider the
performance and availability ramifications for both the
hardware and software.  On the hardware side, there are
issues such as the amount of memory to include in the
coupling facility, how it's allocated among various
structures, and the number of coupling facility channels for
each central processor complex (CPC).  On the software side,
issues revolve around the number of software products that
will use the coupling facility channels, and the kind of data
sharing you plan to implement in the sysplex.

As you gradually build up your sysplex, it is advisable to
incrementally add applications and workload to the data
sharing environment.  As you do so, monitor the structure
sizes, request types (synchronous/asynchronous) and volume,
queuing levels, and service times.

The XCF Channel Activity report can be used to assess overall
request activity on the sysplex, as well as path and
subchannel availability.  The Coupling Facility Configuration
report can be used to more closely examine the request
activity going through particular coupling facility list
structures.