z/OS communicates problems through messages that it writes to logs.

Do not overlook log data — it should be the first place to look when reviewing a problem. The following six logs contain the primary sources of problem data:

SYSLOG

The SYSLOG is a SYSOUT data set provided by the job entry subsystem (either JES2 or JES3). SYSOUT data sets are output spool data sets on direct access storage devices (DASD). An installation should print the SYSLOG periodically to check for problems. The SYSLOG consists of:

• All messages issued through WTL macros
• All messages entered by LOG operator commands
• Usually, the hard-copy log
• Any messages routed to the SYSLOG from any system component or program

View SYSLOG through the Spool Display and Search Facility (SDSF) using the LOG option. A small amount of the SYSLOG is also stored in memory and is included when an address space is dumped. This is referred to as master trace (MTRACE) data and can be accessed from IPCS using the VERBX MTRACE command.

This example shows the MVS SYSLOG without time stamps.

STC18213 00000090 $HASP100 BPXAS ON STCINRDR
STC18213 00000090 $HASP373 BPXAS STARTED
STC18213 80000010 IEF403I BPXAS - STARTED - TIME=13.36.36 - ASID=001F - SC53
STC16316 00000291 IST663I IPS SRQ REQUEST FROM ISTAPNCP FAILED, SENSE=08570002
     111 00000291 IST664I REAL OLU=USIBMSC.S52TOS48 REAL DLU=USIBMSC.S48TO
     111 00000291 IST889I SID = ED0385CAAEEAAF28
     111 00000291 IST264I REQUIRED RESOURCE S48TOS52 NOT ACTIVE
     111 00000291 IST314I END
STC16352 00000291 IST663I IPS SRQ REQUEST FROM ISTAPNCP FAILED, SENSE=087D0001
     883 00000291 IST664I REAL OLU=USIBMSC.S52TOS48 ALIAS DLU=USIBMSC.S48TO
     883 00000291 IST889I SID = ED0385CAAEEAAF28
     883 00000291 IST314I END
STC28215 00000291 IST663I IPS SRQ REQUEST TO ISTAPNCP FAILED, SENSE=08570002 86
     864 00000291 IST664I REAL OLU=USIBMSC.S52TOS48 ALIAS DLU=USIBMSC.S48TO
     864 00000291 IST889I SID = ED0385CAAEEAAF28
     864 00000291 IST264I REQUIRED RESOURCE S48TOS52 NOT ACTIVE
     864 00000291 IST891I USIBMSC.SC48M GENERATED FAILURE NOTIFICATION
     864 00000291 IST314I END

Job log

Messages sent to the job log are intended for the programmer who submitted a job. Specify the system output class for the job log in the MSGCLASS parameter of the JCL JOB statement.

OPERLOG

Operations log (OPERLOG) is an MVS system logger application that records and merges messages about programs and system functions (the hardcopy message set) from each system in a sysplex that activates OPERLOG.

In SDSF the OPERLOG panel displays the merged, sysplex-wide system message log. You can use parameters of the LOG command to select the OPERLOG panel or the single-system SYSLOG panel. The OPERLOG panel displays the data from a log stream, a collection of log data used by the MVS System Logger to provide the merged, sysplex-wide log.

An individual product has its own log file. These log files might contain data that is valuable when diagnosing a problem. It is particularly important to look for events that precede an actual abend or failure because the problem, in many cases, will have been caused by a previous action.

This example shows the SYSOUT data sets that might be associated with a CICS® address space:

NP DDNAME    StepName ProcStep DSID Owner
   JESJCLIN                      1 CICSTS
   JESMSGLG   JES2               2 CICSTS
   JESJCL     JES2               3 CICSTS
   JESYSMSG   JES2               4 CICSTS
   $INTTEXT   JES2               5 CICSTS
   CAFF       SCSCPAA1         101 CICSTS
   CINT       SCSCPAA1         103 CICSTS
   DFHCXRF    SCSCPAA1         104 CICSTS
   COUT       SCSCPAA1         105 CICSTS
   CEEMSG     SCSCPAA1         106 CICSTS
   CEEOUT     SCSCPAA1         107 CICSTS
   PLIMSG     SCSCPAA1         108 CICSTS
   CRPO       SCSCPAA1         109 CICSTS
   MSGUSR     SCSCPAA1         110 CICSTS

The key SYSOUT data sets to review for problem determination data are the JESMSGLG and MSGUSR data sets. The CEEMSG and CEEOUT data sets will contain Language Environment® (LE) problem data typically associated with application problems.

The CICS JESMSGLG SYSOUT data set includes information related to CICS startup and errors related to system problems, not specifically transaction related.

Logrec Error Recording

Logrec log stream is an MVS System Logger application that records hardware hardware errors, selected software errors, and symptom records across the sysplex.

Use the records in the logrec data set or the logrec log stream as additional information when a dump is produced. The information in the records can point you in the right direction while supplying you with symptom data about the failure. Use the Environmental Record, Editing, and Printing program (EREP) to:

• Print reports about the system records
• Determine the history of the system
• Learn about a particular error

Logrec data is written to the SYS1.LOGREC data set and is also written to internal storage that is included in a dump. The SYS1.LOGREC data set can be interrogated using the ICFEREP1 program, or if the abend has triggered a dump, the EREP data can be reviewed using the IPCS VERBX LOGDATA command. Generally, the error log entries at the end of the display, if they have an influence on the problem being reviewed, have time stamps that relate to or immediately precede the actual abend; although there is no guarantee the error records will be written in the order they occurred. The error log entries are also written to an internal storage buffer that is included in the dump.

Using a logrec log stream rather than a logrec data set (SYS1.LOGREC, by default) for each system can streamline logrec error recording.

Console log

Console data that the installation chooses to log.

Hardcopy log

The hardcopy log is a record of the system message traffic that the installation chooses to log, such as messages to and from all consoles, commands and replies entered by the operator. In a dump, these messages appear in the master trace. With JES3, the hardcopy log is always written to the SYSLOG. With JES2, the hardcopy log is typically written to the SYSLOG but can be written to a console printer, if your installation chooses.