How Runtime Diagnostics works

Note: Runtime Diagnostics is a diagnostic tool to run in your environment when your system experiences symptoms that require its use. Run it when you experience system degradation or if you want to check for potential problems; do not run when the system is operating normally. IBM® Service might also request that you run Runtime Diagnostics and report its results.
After you start Runtime Diagnostics (S HZR,SUB=MSTR), you can analyze the home system by entering the following MODIFY (or F) command.
MODIFY HZR,ANALYZE
or 
F HZR,ANALYZE
Runtime Diagnostics searches for certain messages and message combinations in the operations log (OPERLOG) stream and attempts to identify other system symptoms with minimal dependencies on other system services. By default, Runtime Diagnostics analyzes the home system.
If you want Runtime Diagnostics to analyze a different system, specify the system name on the MODIFY command by entering the SYSNAME parameter: 
F HZR,ANALYZE,SYSNAME=SYSB

For example, if you are using Runtime Diagnostics on the home system, such as SYSA, all analysis is for the home system. If you must analyze a system other than SYSA, such as SYSB, specify F HZR,ANALYZE,SYSNAME=SYSB. When you use this method, Runtime Diagnostics analysis is limited to critical messages in OPERLOG and ENQ information.

Typically when analyzing a system, Runtime Diagnostics runs for less than one minute. It can take more time; it depends on how many systems are in your environment. For example, if Runtime Diagnostics analyzes four systems in a Parallel Sysplex® environment, it must analyze OPERLOG messages from each system in the sysplex to determine which messages are issued by the target system. This analysis takes more time than analyzing a single system where all messages are issued by the target system.

When Runtime Diagnostics finds a problem, it displays a multi-line write-to-operator (WTO) message that lists system error events. The message contains a problem description and a suggested next action for your analysis.

Parent topic: Runtime Diagnostics