DASD space allocation

The number of OAM SMF records written to the SMF data sets is dependent on two major factors:

• The amount of OAM activity that occurs on the processor complex, and
• The OAM SMF record subtypes that the system programmer has selected to be recorded in the SMF data sets.

Depending on the number of SMF records being recorded in the SMF data sets, the system programmer should perform the following activities:

• Determine which OAM SMF record subtypes should be captured.
• Make a preliminary determination of the number of each OAM SMF record subtype that will occur each hour or day.
• Calculate the additional DASD space requirements needed for SMF data sets based on the above two factors. The OAM SMF record subtype sizes are provided in the Table 1. Variables and formulas for determining DASD requirements can be found in Table 1, Table 1, and Table 1.
• Determine if the DASD space allocation quantities for the existing SMF data sets will be satisfactory given the additional space required by the OAM SMF records. If the DASD space allocation quantity for the existing SMF data sets is insufficient based on how frequently the system programmer wishes SMF to switch data sets, perform one or both of the following:
  • Reallocate the SMF data set with a larger primary space allocation quantity
  • Increase the number of SMF data sets
• Determine the adequacy of the DASD subsystem containing the SMF data sets to determine if the additional I/O activity caused by OAM recording the selected SMF records is going to introduce unacceptable levels of utilization and I/O contention on the DASD subsystem components, including:
  • DASD device level I/O contention
  • Control unit I/O contention
  • Channel path contention and utilization