GFTASRT3—Tape Data Set Size Range Report

GFTASRT3 shows the most current version of each particular data set found during the sample. If ten copies of a data set exist on tape, this part of the report only includes the latest version.

This report shows the number of data sets in each size range and the mount activity that is attributed to the data sets in that range. If you specify CHART (see CHART Keyword), the raw numbers from this report are put out to the sequential data set defined by the VMACHART DD statement.

If you specify the GDG(GROUP) keyword, the numbers in the Tape Data Set Size Range Report reflect non-GDG data sets and GDG data sets grouped together and counted as one generation data group.

Note: You should not try to match these numbers to those from the volume summary report (GFTASRT2) because they simply do not equate. The numbers in GFTASRT3 are from the data set perspective while the numbers in GFTASRT2 are from the volume perspective.

Figure 1 is the report that summarizes data set sizes for this run. In this report, keywords were not specified.

Figure 1. GFTASRT3 Summary Report—Tape Data Set Analysis

            10a                           10b 
+----------------------------------------------------------------------------------------------------+
|                              GFTASRT3 -- TAPE DATA SET SIZE RANGES                                 |
+--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----+
|        |  # OF |% TOT| CUM # |% TOT|# OF STAT|% TOT| CUM STAT|% TOT|# OF STAT|% TOT| CUM STAT|% TOT|
|DSN SIZE|  DSNS | DSNS|  DSNS | DSNS|  MOUNTS | MNTS|  MOUNTS | MNTS| VOLUMES | VOLS| VOLUMES | VOLS|
+--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----+
| =  0 MB|   2568|  6.2|   2568|  6.2|   1277.8|  3.3|   1277.8|  3.3|    192.6|  3.0|    192.6|  3.0|   11 
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=  1 MB|  21368| 51.8|  23936| 58.0|  15173.7| 39.3|  16451.5| 42.6|   2480.8| 39.1|   2673.4| 42.2|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=  5 MB|   4870| 11.8|  28806| 69.9|   3532.6|  9.2|  19984.1| 51.8|    667.8| 10.5|   3341.2| 52.7|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<= 10 MB|   2203|  5.3|  31009| 75.2|   2125.0|  5.5|  22109.1| 57.3|    412.5|  6.5|   3753.6| 59.2|   12 
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<= 25 MB|   2852|  6.9|  33861| 82.1|   3379.6|  8.8|  25488.7| 66.1|    524.6|  8.3|   4278.2| 67.5|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<= 40 MB|   1888|  4.6|  35749| 86.7|   1877.3|  4.9|  27366.0| 70.9|    345.3|  5.4|   4623.5| 72.9|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<= 50 MB|    691|  1.7|  36440| 88.4|    670.6|  1.7|  28036.5| 72.7|    122.2|  1.9|   4745.7| 74.9|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<= 75 MB|   1382|  3.4|  37822| 91.7|   1828.4|  4.7|  29865.0| 77.4|    274.8|  4.3|   5020.5| 79.2|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=100 MB|    710|  1.7|  38532| 93.4|    991.4|  2.6|  30856.3| 80.0|    143.1|  2.3|   5163.6| 81.5|   13 
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=125 MB|    502|  1.2|  39034| 94.7|    708.0|  1.8|  31564.3| 81.8|     94.0|  1.5|   5257.6| 83.0|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=150 MB|    141|  0.3|  39175| 95.0|    195.7|  0.5|  31760.0| 82.3|     37.4|  0.6|   5295.0| 83.5|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=175 MB|    245|  0.6|  39420| 95.6|    350.5|  0.9|  32110.6| 83.2|     68.6|  1.1|   5363.6| 84.6|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=200 MB|    335|  0.8|  39755| 96.4|    357.0|  0.9|  32467.6| 84.1|     71.9|  1.1|   5435.5| 85.8|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=300 MB|    586|  1.4|  40341| 97.8|    768.4|  2.0|  33236.0| 86.1|    146.4|  2.3|   5581.9| 88.1|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=400 MB|    257|  0.6|  40598| 98.4|    587.0|  1.5|  33823.0| 87.7|    127.2|  2.0|   5709.1| 90.1|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=500 MB|     49|  0.1|  40647| 98.6|    203.3|  0.5|  34026.4| 88.2|     20.3|  0.3|   5729.3| 90.4|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=600 MB|    174|  0.4|  40821| 99.0|    547.4|  1.4|  34573.7| 89.6|    120.8|  1.9|   5850.1| 92.3|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=700 MB|     21|  0.1|  40842| 99.0|    466.6|  1.2|  35040.4| 90.8|     50.0|  0.8|   5900.1| 93.1|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=800 MB|     30|  0.1|  40872| 99.1|    512.0|  1.3|  35552.4| 92.1|     78.0|  1.2|   5978.1| 94.3|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=900 MB|     57|  0.1|  40929| 99.3|    760.0|  2.0|  36312.4| 94.1|    100.0|  1.6|   6078.1| 95.9|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=  1 GB|     84|  0.2|  41013| 99.5|    829.3|  2.1|  37141.6| 96.3|    114.6|  1.8|   6192.7| 97.7|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=  2 GB|    216|  0.5|  41229|100.0|   1381.1|  3.6|  38522.8| 99.8|    137.4|  2.2|   6330.1| 99.9|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=  3 GB|      6|  0.0|  41235|100.0|     50.0|  0.1|  38572.8|100.0|      4.0|  0.1|   6334.1| 99.9|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=  4 GB|      1|  0.0|  41236|100.0|      4.0|  0.0|  38576.8|100.0|      2.0|  0.0|   6336.1|100.0|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|<=  5 GB|      1|  0.0|  41237|100.0|      4.0|  0.0|  38580.8|100.0|      2.0|  0.0|   6338.1|100.0|
|--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----|
|>   5 GB|      1|  0.0|  41238|100.0|      4.0|  0.0|  38584.8|100.0|      0.0|  0.0|   6338.1|100.0|
+--------+-------+-----+-------+-----+---------+-----+---------+-----+---------+-----+---------+-----+
GFTAVMA PROGRAM COMPLETED AT 03:45:37 P.M. ON 05/21/2004 -- RETURN CODE =  0

This report shows the sizes of your data sets and the number of mounts these data sets caused. If small data sets are causing most of your mounts, as they are in this example, you are using your tape media inefficiently.

10 Compare the number of data sets in each of the size ranges. Notice that the majority of the data sets are in the smaller size ranges while fewer data sets are in the large size ranges. The data set size (DSN SIZE) and number of mounts (CUM STAT MOUNTS and % TOT MNTS) show that the smaller data sets caused most of the mounts in this example.

11 Two-thousand-five-hundred-sixty-eight data sets are equal to 0MB and account for 1277.8 mounts. These data sets were opened, but had no read or write activity. These data sets should not have caused tape mounts because there was no transfer of data. These mounts could have been avoided by directing these data sets to the tape mount management DASD buffer.

12 This sample is typical in that the majority of data sets on tape are small, yet they account for most of the mounts. For example, 75.2% of the data sets analyzed are less than or equal to 10MB, but they account for 57.3% of all tape mounts in this run.

13 Small data sets, less than or equal to 100MB, are causing 80% of the mounts in this example, which indicates that tape mount management could significantly reduce the number of mounts for this installation.