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Changing SMF Options

You can change the SMF options in effect on the system. These changes can be made in several ways. Because SMF options are specified in a SMFPRMxx member of the logical Parmlib, it is common for changes to be made using ISPF/PDF Edit. Normally, ISPF/PDF statistics indicate when the change was made and by whom. However, these statistics are not reliable because they can be altered or removed. The IBM IEBUPDTE utility does not provide statistical information if it makes parmlib modifications.

Depending on the SMF options chosen for the data center, the console operator can choose an alternate SMF parmlib member or to alter individual parameters through the operator prompt and reply process during IPL. The SMF PROMPT(LIST) and PROMPT(ALL) parameters permit SMF changes during IPL.

The computer operator can also use the SET SMF command after IPL to change SMF operations. The SET SMF command cannot be disabled without z/OS modifications. In addition to the SET SMF command, the SETSMF command permits operators to alter individual SMF parameters. Although the names of these commands are very similar, the SET SMF and SETSMF commands are completely different in purpose and function. The data center can disable operator use of the SETSMF command by using the SMF PROMPT(IPLR) or NOPROMPT parameter.

The PROMPT(ALL) or PROMPT(IPLR) SMF parameters require the operator to enter a reason for each IPL. Operations and technical support staffs should review all unscheduled IPLs on a regular basis. You can see what the operator entered for a reason by reviewing the SMF type 90 record with the SMF Search Option (1.5.4).

Although the SMF options can specify that key SMF records be recorded, SMF exits can suppress these records. The IEFU83, IEFU84, and IEFU85 SMF exits are expressly provided to suppress records. IEFU83 is called by SVC 83 and IEFU84 and IEFU85 are branch‑entered. The SMF Exits Display (1.5.3) shows you if these exits are present in the system.