Retention methods

Among the important decisions to be made when using DFSMSrmm are how to retain tape data sets and for how long. You might want to retain a given data set for a specific period of time after it is created, or retain it based on some event (for example, while the data set is catalogued or when it was last used), or retain it permanently.

DFSMSrmm provides two retention methods for retaining tape data sets:

The EXPDT retention method, which allows expiration to be on a specific date or based on an event (retention for a specific number of days after last use)..
The VRSEL retention method, which uses vital record specifications to implement retention and movement policies through which a retention date is calculated each time that VRSEL inventory management processing is run. DFSMSrmm retains a volume based on this retention date and on the volume expiration date.

The retention method is an attribute of the volume. All volumes in a multivolume set have the same retention method. All data sets on a volume are managed with the same retention method as the volume on which they reside. DFSMSrmm will assign a retention method to a new single volume or new multivolume set when the first tape data set of the single volume or first volume of the multivolume set is created. The retention method can be set in the:

Default retention method that is specified in the DFSMSrmm parmlib option.
DFSMSrmm installation exit EDG_EXIT100, if the (generic) data set name is specified.
RMM ADDVOLUME command using the RETENTIONMETHOD parameter.