MustGather information for z/OS

The more information that you can collect about a problem, the easier it is to diagnose that problem. A large set of data can be collected, although some is relevant to particular problems.

The data that is collected from a fault situation in z/OS® depends on the problem symptoms, but could include some or all of the following information:

• Transaction dump - an unformatted dump that is requested by the MVS BCP IEATDUMP service. For more information, see Setting up dumps. This dump can be post-processed with the dump viewer (see Using the dump viewer in the OpenJ9 user documentation), the dbx debugger, or IPCS (Interactive Problem Control System).
• CEEDUMP - formatted application level dump, requested by the cdump system call.
• Javadump - formatted internal state data that is produced by the IBM® VM.
• Binary or formatted trace data from the JVM internal high performance trace. See Using method trace in the OpenJ9 user documentation and Tracing Java applications in the J9 VM reference.
• Debugging messages that are written to stderr. For example, the output from the JVM when switches like -verbose:gc, -verbose, or -Xtgc are used.
• Java™ stack traces when exceptions are thrown.
• JIT dump - a binary file of diagnostic data that is produced by the JVM in response to a GPF or abort event. For more information, see JIT dumps in the OpenJ9 user documentation.
• Other unformatted system dumps obtained from middleware products or components (for example, SVC dumps requested by WebSphere® for z/OS).
• SVC dumps obtained by the MVS Console DUMP command (typically for loops or hangs, or when the IEATDUMP fails).
• Trace data from other products or components (for example LE traces or the Component trace for z/OS UNIX).
• Heapdumps, if generated automatically, are required for problem determination. You should also take a Heapdump if you have a memory or performance problem.