Data Set Stacking

Data set stacking places several data sets on the same tape volume or set of tape volumes. It is used to accomplish the following:

Increase efficiency of tape media usage
Reduce the overall number of tape volumes needed when allocating new data sets

To request data set stacking, you must have the following JCL options on the DD statement:

Data-set-sequence-number subparameter on the LABEL parameter is greater than one.
This subparameter is used to identify the relative position of a data set on a tape volume. For existing cataloged data sets, the system obtains the data-set-sequence-number from the catalog.
VOL=SER or VOL=REF parameter
This parameter indicates the tape volume or volumes on which to stack. When VOL=SER is used, at least one of the volume serial numbers specified must match one of the volume serial numbers for the data set on which this data set is being stacked (either explicitly specified or obtained from the catalog). Use VOL=SER when stacking multi-volume, multi-data sets within the same job step.

Related Reading: For more recommendations on when to use VOL=REF versus VOL=SER, see z/OS MVS JCL User's Guide.

The following example shows data set stacking using VOL=SER.

//P123456 JOB
//STEP1   EXEC
//D1      DD   DSN=A,DISP=(NEW,CATLG),VOL=SER=(VOL1,VOL2),
//             UNIT=TAPE,LABEL=(1,SL)
//D2      DD   DSN=B,DISP=(NEW,CATLG),VOL=SER=VOL2,
//             UNIT=TAPE,LABEL=(2,SL)
//