Problem

On z/OS (MVS) CFT, how does the CFTLOG switch happen?

Resolution

CFTLOG is switched in one of several ways:

- CFTLOG's SWITCH (time) parameter (the most used method, at 00:00:00)

- CFTLOG's MAXREC (number of records) parameter

This option can be combined with the SWITCH time. When both parameters are specified, the CFTLOG will switch when the number of records reaches the MAXREC value AND the SWITCH time.

- Manual SWITCH TYPE=LOG Command

- On CFT SHUT: command (UCONF parameter cft.cftlog.switch_on_stop=YES (default is NO))

- On CFT Startup: (up to version 3.6)

- On CFT Startup: (from version 3.7) the switch is conditionned by UCONF cft.cftlog.switch_on_start

- In addition, z/OS (MVS) only, when the CFTLOG file is full condition (x37 Error) is encountered:

IEC031I D37-04,IFG0554P,RTANICFT,CFTMAIN,FIL00007,266A,GCS9A2, 935 GCSSUP.RTANI.V36.LOG1
CFTS33I CFTLOG current file before switch :GCSSUP.RTANI.V36.LOG1
CFTS34I CFTLOG execute switch procedure : GCSSUP.RTANI.V36.EXEC(SWILOG)
CFTS35I CFTLOG current file after switch :GCSSUP.RTANI.V36.LOG2

When CFTLOG Switch happens, CFT will start to write the LOG entries to the alternate LOG file, then the JCL specified by the CFTLOG EXEC is executed to make a copy (optional) of the current LOG file passed by &LOG variable and empty the current LOG file.

Up to CFT 3.6, at least one of the LOG files (LOG1/LOG2) must be empty for the CFT start or to continue the operation.

From CFT 3.7 and above, the same LOG file can be used until it is full or the switch time is raised (related to UCONF variable cft.cftlog.switch_on_start / cft.cftlog.switch_on_stop)

CFTLOG's OPERMSG parameter controls what's written to the Operator Console (JES2 Syslog), but CFT will always write everything into the CFTLOG file.

CFTLOG's CONTENT=[FULL | BRIEF] can be used to control the amount of data written to the CFTLOG file.