Research Your System

• Analyze the Media Database using utility CTTRPT. A wide variety of reports can be generated through this utility. Some examples of how this utility can be used to extract information for stacking implementation are listed below.
  • List under-utilized volumes (through the CTTRUTIL sample report). The volumes in this report are sorted by used capacity to help identify the best candidate volumes for stacking implementation.
  • Sort the inventory by data set name. Usually this results in sorting the data sets according to application (due to naming conventions).

  Sample CTTRPT reports are located in the IOA SAMPLE library. For more information about the CTTRPT utility, see the Control-M/Tape chapter of the INCONTROL for z/OS Utilities Guide.

• Identify candidate data sets for stacking implementation. Selection of data sets should depend on:
  • the type of application that generated the data sets
  • which data sets belong to an application that frequently encounters a shortage of scratched volumes
  • the size of relevant data sets
  • which data sets are assigned to each pool (if pools are in use at the site)
• If you are working with STKMODE set to R or A, data sets for which retention is not a specific date or number of days (for example, retention type CATALOG, CYCLES, or LAST ACCESS) are stacked according to their average life span. The Dynamic Data Set Stacking facility calculates the expected expiration date of each such data set (from information in the Stacking Database) and stacks them according to the requested search algorithm.

  If you prefer that data sets with non-specific retention be handled in a different way, generate a list of these data sets through the CTTRPT report utility, and define Control-M/Tape rules that include the DO STKMODE=S statement for these data sets.

• Identify potential conflicts (meaning, data sets that should not be stacked together). The CTTSCA Control-M/Tape utility can be used to automatically detect certain types of conflicts and to generate rules that prevent those conflicts from occurring. For more information, see the Control-M/Tape chapter of the INCONTROL for z/OS Utilities Guide.
• Identify groups of data sets that should reside together. These data sets should be identified as stacking groups through DO STKGROUP statements in Control-M/Tape rules.