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Source: VCADAA file at the DETAIL timespan
Function: This report helps to identify departments or
groups that are wasting DASD storage space due to
poor allocation practices. These problems can be
caused either by allocating more space than is
necessary, or by using an inefficient block size.
The Storage Administrator can analyze either or
both of these causes with the same report.
Correction of the problems detected by this report
may recover a large amount of storage space with a
small amount of effort.
Features: The left side of the report shows total space
space wasted by each group due to the two causes
described above, and also displays the amount of
space wasted in megabytes by the most wasteful
data set in the group. The middle portion of the
report shows statistics related to poor block
sizes, while the right side of the report
summarizes waste due to overallocation of space.
The owner of the data can be defined by one or
more data set nodes, one or more account fields,
or through an external table. This report can be
run regularly to monitor wasted space, with more
detailed reporting run when problems are detected.
Generation of the summary report is automatic.
SMS
Issues: Users planning for SMS could identify those groups
with the worst space usage values, as they may be
the best candidates for the immediate benefits of
SMS. As groups migrate to SMS control, regular
use of this report would verify that the expected
space savings from SMS are being realized.
COLUMN DESCRIPTIONS
Data Owner
The value used as the summarization key for this
report. Depending on the values specified on the
report option screen, this will represent one or
more VCA account elements, one or more nodes of
the data set name, or will contain a value derived
from your Data Set Group table.
Total Data Sets
The total number of data sets found for this
summarization group in the data being analyzed.
This value will be affected by the filtering
criteria specified on the report option screen,
especially if Max Data Sets was coded. The Max
Data Sets option allows only a specified number of
the worst data sets to be selected, in terms of
wasted space. This option is valuable for
reducing the size of the detail report, but will
skew the results if you are trying to obtain an
overview of all users.
Total MBytes Wasted
The total amount of DASD space being wasted by the
data sets in this summarization group, expressed
in millions of bytes (megabytes). This includes
the space wasted due to poor block size (Blksize
MBytes Wasted column), plus the space wasted due
to over-allocation of space (OverAloc MBytes
Wasted column).
Blksize MBytes Wasted
The total amount of DASD space being wasted by the
data sets in this summarization group due to poor
block size. For each data set, waste per track is
first calculated by multiplying the block size by
the blocks per track, and subtracting that value
from the maximum track capacity for the device.
That value is then multiplied by the number of
tracks being used (not allocated) by the data set.
This value will be zero if ALLOC analysis was
specified on the report option screen when
generating this report.
OverAloc MBytes Wasted
The total amount of DASD space being wasted by the
data sets in this summarization group due to over-
allocation of space. This is calculated for each
data set by subtracting tracks used from tracks
allocated, and multiplying that amount by the
maximum track capacity for the device. This value
will be zero if BLOCK analysis was specified on
the report option screen when generating this
report.
Worst Data Set
The amount of DASD space, expressed in millions of
bytes (megabytes) being wasted by the worst data
set within this summarization group. This would
be the data set that is wasting the largest amount
of space of all data sets within the summarization
group. You may want to run this report again
using different values on the report option screen
to identify the names of individual data sets that
are wasting space.
Min Block Size
The smallest block size value found for all the
data sets in this summarization group. This helps
to identify groups that may be using small block
sizes, which tend to waste space.
Avg Block Size
The average block size found for all the data sets
in this summarization group. This is calculated
as the sum of the block size value for each data
set, divided by the number of data sets in the
summarization group. This helps to identify
groups that may be using small block sizes, which
tend to waste space.
Avg# Blks Trk
The average number of blocks being stored on each
DASD track for all the data sets in this
summarization group. This is calculated as the
sum of the number of blocks per track for each
data set, divided by the number of data sets in
the summarization group. This helps to identify
groups that may be using poor block size values,
as they will tend to write a larger number of
blocks per track.
Avg % Track Waste
The average percentage of each track being wasted
by the data sets in this summarization group
because of block size factors. This is calculated
by computing the maximum and actual number of
bytes used per track for each data set, summing
both of these values for all data sets in the
summarization group, and then dividing the
difference between the two sums by the sum of
maximum space. This helps to identify groups that
may be using poor block size values, as they will
have a large percentage value in this column.
Total Tracks Alloc
The total number of tracks being allocated by all
the data sets in this summarization group.
Total Tracks Used
The total number of tracks actually being used to
contain data for each of the data sets in this
summarization group. The difference between the
Total Tracks Alloc value and this value indicate
the number of tracks that are being wasted by data
sets in this group due to over-allocation.
Avg % Alloc Waste
The average percentage of the allocated tracks for
all data sets within this summarization group that
are not being used to contain data. This is
calculated by subtracting the Total Tracks Used
value from the Total Tracks Alloc value and
dividing that by Total Tracks Alloc. This helps
to identify groups that are over-allocating their
data sets, as they will have large percentage
values in this column.
NON-VSAM WASTED SPACE (STGECC) 4 CA MICS StorageMate - SUMMARY ABC CORPORATION ------------------------------------------------------------ SYSID=SYS7 ------------------------------------------------------------ Data Owner Total Total Blksize OverAloc Worst | Min Avg Avg# Avg % | Total Total Avg % Data MBytes MBytes MBytes Data | Block Block Blks Track | Tracks Tracks Alloc Sets Wasted Wasted Wasted Set | Size Size Trk Waste | Alloc Used Waste CUSTOMER-SUPPORT 4 271 121 150 141 | 0 32760 1 30 | 11760 8560 27 DEVELOPMENT 20 826 316 510 114 | 6160 31430 1 41 | 33046 22154 33 DISTRIBUTION-LIBS 3 168 0 168 117 | 6160 15027 5 91 | 3600 0 100 MARKETING-SALES 61 2971 990 1981 290 | 0 26774 6 54 | 91649 49448 46 SYSTEM-DATA 12 1346 192 1154 620 | 0 12191 15 93 | 33935 9363 72 ---------------------------------------- ------ -------- -------- -------- ------- ------- SYSID 100 5582 1619 3963 173990 89525 ====== ======== ======== ======== ======= ======= 100 5582 1619 3963 173990 89525
Figure 4-54. Non-VSAM Wasted Space / Summary
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