Runtime Diagnostics

Runtime Diagnostics is a base component (HZR) of z/OS® that is designed to help you analyze a system that has a potential problem or soft failure. Soft failures are often difficult or impossible to detect and can slowly lead to the degradation of the solution that is using z/OS. To understand soft failures, see the definition in Predictive Failure Analysis overview and installation.

Runtime Diagnostics does many of the same tasks you might typically do when looking for a failure, such as:

Reviewing critical messages in the log
Examining address spaces with high processor usage
Looking for an address space that might be in a loop
Evaluating local lock conditions
Analyzing various types of contention that include ENQ, GRS latch contention, and z/OS UNIX file system latch contention.

In many cases, when Runtime Diagnostics finds a critical message, it does additional analysis based on the job name or other information in the message text. For example, if Runtime Diagnostics identifies an XCF stalled connector message, it performs additional analysis of the identified address space to help narrow down the problem. A key feature of Runtime Diagnostics is its ability to summarize internal processing errors and return the results to you in a message response.

Predictive Failure Analysis (PFA) can also return Runtime Diagnostics report information when activity is absent or unusually low for:

For details, see How PFA invokes Runtime Diagnostics.

This section covers the following topics: