If any form of CICS journaling or logging is required and any form of CICS start other than INITIAL then the machine that CICS TS is running in MUST be in some form of SYSPLEX configuration if only a MONOPLEX. CICS now uses the zOS logger and has done away with its own journaling (DFHJCT tables and DFHRSD datasets etc) although it can be configured to use DASD-only logs rather than logging to a Coupling Facility.
CICS System Log (DFHLOG)
This is used for internal CICS logging and is the rough equivalent of the old DFHJ01 plus some more.
Used for recovery purposes (DTB, emergency restart).
CICS needs it to backout recoverable resources, COLD starts (recover a conversation state), WARM starts (pre-shutdown state), EMERGENCY start….
CICS connects to the system log automatically during initialisation.
Default names: region_userid.applid.DFHLOG and ….DFHSHUNT
Whenever a new set of System Logs are defined, or if they are to be cleared down CICS must be started with START=INITIAL.
Example to define the CICS System log streams….
//SYS013 EXEC PGM=IXCMIAPU
//SYSPRINT DD SYSOUT=*
//SYSIN DD *
DATA TYPE(LOGR) REPORT(YES)
DELETE LOGSTREAM NAME(CICS.DFHLOG.MODEL)
DEFINE LOGSTREAM NAME(CICS.DFHLOG.MODEL)
MODEL(YES)
DASDONLY(YES)
LOWOFFLOAD(40)
HIGHOFFLOAD(80)
STG_SIZE(9094)
MAXBUFSIZE(64000)
DELETE LOGSTREAM NAME(CICS.DFHSHUNT.MODEL)
DEFINE LOGSTREAM NAME(CICS.DFHSHUNT.MODEL)
MODEL(YES)
DASDONLY(YES)
MAXBUFSIZE(64000)
/*
DFHLGLOG is the CICS log of logs and is used for Forward Recovery products like CICSFR. We, and most other sites, have defined it as DUMMY.
Unless otherwise specified a HLQ of IXGLOGR is prefixed to the logstream name defined in CICS.
May need to define an alias for IXGLOGR and make definitions in TSS.
Check SMS definitions.
Some thought should be given to adequate sizing for a production workload.
CICS supplies a utility (DFHLSCU) to read old style production logs and to predict efficient parameters for your new logstreams.
Deleting and listing of logstreams should also be done using the IXCMIAPU utility.
User Journals and Forward Recovery logs
These are defined in a similar way. They can / should be defined to manage themselves (e.g. keep data for a specific time). Due to the nature of the processing at Dixons it is unlikely that any such logs will need to be defined.
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