The Statistical Volume Savings Breakdown provides the details for the Statistical Volume Savings reported in the Savings/Cost Summary (Figure 1). The total number of current statistical volumes is arranged by tape mount management data set category, and savings are attributed to the particular management class that would have been assigned based on the specified values for L0AGE and L1AGE.

Figure 1 is the second breakdown report. This report is identical to the Statistical Mounts Savings Breakdown report except that the values are STATISTICAL VOLUMES instead of STATISTICAL MOUNTS.

Figure 1. Estimate Report—Statistical Volume Savings Breakdown

 7  In this example, the current statistical volumes value (CURR STAT VOLUMES) for active data sets is 86.8. The target statistical volumes (TARG STAT VOLUMES) is set to the HSM - LEVEL 2 TARG VOL# for the ACTIVE, ACTV GDG, and BACKUP categories, so these numbers are the same.

The estimated target statistical volumes value if you used DFSMS to manage tape data sets would be 9.9.

This reduction from 86.8 to 9.9 is significant because 18.7 of the 86.8 volumes of active data sets are still residing on primary DASD. The rest of the volumes (68.1) have been reduced to 9.9 volumes because of managing tape data sets in the storage hierarchy and using 3490E tape hardware and Enhanced Capacity Cartridge System Tapes. See Statistical Volumes for more details.

 8  For ACTV GDG data sets, the values in the HSM - LEVEL 2 TARG VOL# column should be equal to the HSM - LEVEL 2 TARG MNT# because when the ACTV GDG volumes are mounted, all the data sets are written to these volumes during one output operation. Thus, full volumes are written.

 9  GFTAVMA models large data sets (greater than the LARGE default of 600MB) as going directly to tape, so DFSMS does not manage them in the storage hierarchy. The volume reduction from 557.8 to 323.8 is based on modelling to the 3490E with the Enhanced Capacity Cartridge System Tape (TAPEDEV of 3490E and TAPELEN of 2), which has a much larger capacity.

 10  In this example, the volume mount analyzer simulates an environment where DFSMShsm bypasses migration level 1 processing. Therefore, the columns for migration level 1 contain zeros. GFTAVMA models the data sets as going directly from primary DASD to migration level 2 tape, bypassing migration level 1 DASD because the LEVEL0AGE and the LEVEL1AGE keywords defaulted to one.