Use XCF Metrics to Help Align Your Sysplex

Rather than having to break up XCF resources based on the size and volume of the messages those resources will handle, the XCF enhancement delivered in z/OS 2.4, ‘Transport Class Simplification,’ enables XCF to group and manage all defined signaling resources as a single logical pool of XCF paths and buffers. This change has proven to be very popular with busy system programmers, who have much better things to do with their time than trawling through not-very-friendly RMF XCF reports.

Because the previous model of breaking up signaling resources resulted in most customers defining more paths and larger buffer pools than are really needed, Transport Class Simplification also presents the possibility of reducing the number of resources defined to XCF.

On the other hand, a potential downside of this new paradigm is an increased possibility of XCF in a very large sysplex, or if huge XCF buffer pools are defined, running out of storage for its buffers in extreme situations – this article describes the risk and provides guidance on how to minimize it. As such, it has something for everyone, from the smallest sysplex up to the largest.

In this latest Cheryl Watson’s Tuning Letter reprint, Todd Havekost discusses the latest XCF-related configuration guidelines from IBM, describes the new XCF metrics that were delivered as part of the transport class simplification enhancements, and illustrates how those metrics can be used to help you align your sysplex with IBM’s recommendations.

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