This IDCAMS DCOLLECT procedure is designed for customers with only active data (having no migrated data). Use DCOLLECT to obtain information (D type records) on the number of active data sets in your storage environment.

You can use the number of D type records that are written to the “OUTDS” data set to estimate the number of active data sets. In the previous calculation, substitute the number of D type records for mds. For more information on IDCAMS DCOLLECT command and all of its parameters, refer to z/OS DFSMS Access Method Services Commands.

//COLLECT1 JOB    ...
  //STEP1    EXEC   PGM=IDCAMS
  //SYSPRINT DD     SYSOUT=A
  //OUTDS    DD     DSN=USER.DCOLLECT.OUTPUT,
  //       STORCLAS=LARGE,
  //       DSORG=PS,
  //       DCB=(RECFM=VB,LRECL=644,BLKSIZE=0),
  //       SPACE=(1,(100,100)),AVGREC=K,
  //       DISP=(NEW,CATLG,KEEP)
  //SYSIN    DD     *
       DCOLLECT -
             OFILE(OUTDS) -
			NOVOLUMEINFO
  /*