In this example, you are backing up data sets with a specified retention period by specifying the RETAINDAYS keyword on the HBACKDS command. RETAINDAYS controls the minimum number of days that a backup copy of a data set is maintained. DFSMShsm uses the RETAINDAYS value to determine when a backup version expires.

HBACKDS (dsname1, dsname2, dsname3,..... dsnamen) RETAINDAYS(days)