Using JOURNALMODELs to define the system log

You might want to use journal models for system logs if the CICS region userid changes between runs (for example, where a test CICS region is shared between application developers).

It would be wasteful to create log streams with a different high level qualifier for each user. Using the same system log stream regardless of the which programmer starts up the CICS region keeps the number of log streams to a minimum. The following example uses a specific JOURNALNAME, with symbols in the STREAMNAME, making this an explicit model for the primary log stream.

  DEFINE GROUP(TEST) DESC('System logs for test CICS regions')
         JOURNALMODEL(DFHLOG) JOURNALNAME(DFHLOG) TYPE(MVS)
         STREAMNAME(TESTCICS.&APPLID..&JNAME.)

If you define JOURNALMODEL resource definitions to define log stream names for DFHLOG and DFHSHUNT, ensure that the resulting log stream names are unique. If you have some CICS regions that use the same applid, you must use some other qualifier in the log stream name to ensure uniqueness.

If you use JOURNALMODEL resource definitions for the system log, these resource definitions must be defined and added to the appropriate group list (using the CSD utility program, DFHCSDUP) before INITIAL-starting CICS.

System logs cannot be TYPE(SMF).

DFHLOG can be TYPE(DUMMY), but you can use this only if you always INITIAL start your CICS regions and there are no recoverable resources requiring transaction backout. CICS cannot perform a cold start, or warm or emergency restart if TYPE(DUMMY) is specified on the JOURNALMODEL definition.

If you do not want to use a system log, perhaps in a test or development region, define a JOURNALMODEL for DFHLOG with type DUMMY, as shown in the following example:

DEFINE  JOURNALMODEL(DFHLOG)   GROUP(CICSLOGS)
        JOURNALNAME(DFHLOG)
        TYPE(DUMMY)

To start a CICS region without a system log, you must ensure that a JOURNALMODEL definition, such as the one shown above, is included in the start-up group list. Use the DFHCSDUP batch utility program to define the required JOURNALMODEL and to add the group to the group list.

DFHSHUNT can be TYPE(DUMMY). This is not recommended, however, because it impairs the ability of CICS to manage the system log.