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This report produces a tabular ranking of devices by either
subchannel identifier or device number (that is, summarized
across subchannels), in descending order of utilization. The
devices reported here include those that are owned by this
system, and those that are shared among multiple systems
within a Cross System Extensions (CSE) complex, if defined.
A run-time execution parameter is used to specify whether the
report should be by subchannel ID or device number. The
information is summarized across the period of time specified
by the user, again as run-time execution parameters.
INTENDED USE:
To provide an analyst with the necessary information about
device activity for the purpose of monitoring what devices
are being used, and at what rates. Such a report might be
used when exploring periods of poor system performance to
detect a DASD bottleneck. Another use might be for
examining what devices are being under-utilized so that
activity can be balanced.
FORMAT:
A tabular report in order by either subchannel identifier
or device number.
The first column of the report contains either the device
number or the device address, depending on which run-time
option was selected. The next three columns contain the
device type, control unit model, and the volume serial
number, if applicable. The remaining columns of the
report are described below:
I/O COUNT - The number of start and resume
subchannels issued to this device over the reporting
period.
I/O %BUSY - The percentage of the time during the
reporting period that this device was busy with I/O
operations.
I/O RATE - The number of start and resume subchannel
operations per second for this device during the
period of the report.
I/O MSEC - The average number of milliseconds
consumed per I/O operation.
PENDING TIME - The sum, for all I/O requests to this
device during the reporting period, of the time
intervals between acceptance of the start function at
the subchannel and acceptance of the first command
associated with the initiation of channel program
execution at the device. The time is shown in
seconds.
CONNECT TIME - The time, in seconds, that this device
was logically connected to the channel path during
the reporting period for the purposes of searching
and transferring data between it and the channel
subsystem.
DISCONNECT TIME - The time, in seconds, that this
device was logically disconnected from the channel
path during the reporting period due to positioning
functions such as Seek and Set Sector operations, and
delays for path reconnection.
ACTONLY TIME - The sum of time that the subchannel
was device-active but not subchannel-active at the
end of an I/O operation or chain of I/O operations
initiated by START SUBCHANNEL. The time is measured
in seconds, and this value includes all I/O requests
to this device during the reporting period.
SAMPLES - The number of measurement facility samples
that took place during the reporting period.
An example of this report is shown in Figure 3-6.
INQUIRY ID:
Tabular Report: VMXTX5
DATA SOURCE (File/Timespan):
VMXXDV01 - DETAIL
DATA ELEMENTS USED:
VMXDVSID - Host Subchannel ID
VMXDVDEV - Device Number
DEVTYPE - Device Type
CUTYPE - Control Unit Type
VOLSER - Volume Serial Number
VMXMSSCH - Count of SSCH and RSCH for This Device
XDVPCBSY - Percent Device Busy
XDVFPNTM - Device Function Pending Time
XDVDCNTM - Device Connect Time
XDVDDCTM - Device Disconnect Time
XDVDAOTM - Device-Active-Only Time
VMXMSAMP - Measurement Facility Samples
XDVSHRD - CSE Shared Volume Indicator
CALCULATIONS:
The detail records for the user-specified reporting period
are extracted from the XDV files, and summarized, using
CA MICS summarization, and across subchannels, if that was
requested. CA MICS summarization is then invoked a second
time to summarize across the reporting period, producing a
single record per device or subchannel ID. The following
calculations are then performed for the report items that
do not come directly from the XDV file:
/* DEVICE I/O RATE ELEMENT - IORATE */
IORATE = VMXMSSCH / DURATION;
/* MILLISECONDS PER I/O - MSEC */
MSEC = MAX(((SUM(XDVFPNTM,XDVDCNTM,XDVDDCTM)/VMXMSSCH)*
1000),0);
If no I/O activity occurred during a reporting period
(VMXMSSCH EQ ZERO) for a device, the data element MSEC is
set to zero.
USAGE CONSIDERATIONS:
Keep in mind that in VM, a single device may have as many
as eight subchannel paths associated with it. Thus, if
this report is produced by subchannel ID, the same device
may appear several times in the report.
+----------------------------------------------------------------------------------------------------------------------------------+ | VMX Device Ranking Report By Percent Device Utilized | | Product Manufacturing Corporation | | | |INQUIRY: VMXTX5 RUN DATE: 18JUNyy | | System ID = VM01 Date = Thursday, May 27, yyyy | | DEVICE I/O TIMES | | ---------------- CONTROL ---------------------------------- -------------------------------------- | | NUMBER TYPE UNIT VOLSER COUNT %BUSY RATE MSEC PENDING CONNECT DISCONN ACTONLY SAMPLES | | 043F 3380K 3880-23 VMBX74 41,219 57.58 11.54 49.91 48.956 250.322 1758.074 0.000 41,219 | | 043C 3380K 3880-23 VMBX71 40,822 56.30 11.43 49.28 162.109 614.331 1235.437 0.000 40,822 | | 0430 3380K 3880-23 VMBX62 71,144 49.84 19.91 25.03 316.606 360.169 1104.109 0.000 71,144 | | 0C50 CTCA 3088-04 5,328 48.32 1.49 323.89 0.325 6.215 1719.164 0.000 5,328 | | 0431 3380K 3880-23 VMBX63 23,194 34.98 6.49 53.89 96.945 136.036 1016.852 0.000 23,194 | | 098C 3380K 3990-2 JES3Q1 18,483 32.65 5.18 63.08 523.655 305.197 337.116 0.000 18,483 | | 07E7 3380D 3880-3 VMCX11 31,362 32.48 8.78 36.99 27.471 730.958 401.687 0.000 31,362 | | 043A 3380K 3880-23 VMBX70 19,817 26.96 5.55 48.60 110.146 226.872 626.114 0.000 19,817 | | 086A 3380E 3880-3 VMOS1E 9,026 25.44 2.53 100.65 25.047 872.984 10.446 0.000 9,026 | | 03B9 3380K 3880-23 VMBX56 25,717 18.09 7.22 25.06 105.506 151.098 387.757 0.000 25,717 | | 0644 3380D 3880-23 VMBPG4 16,393 17.35 4.59 37.80 4.250 336.024 279.369 0.000 16,393 | | 03FD 3390-2 3990-3 TVS105 13,425 17.02 3.76 45.29 64.849 539.754 3.375 0.000 13,425 | | 0646 3380D 3880-23 VMBPG5 23,443 16.87 6.57 25.70 6.090 214.187 382.128 0.000 23,443 | | 03B6 3380K 3880-23 VMBX54 19,760 15.18 5.55 27.36 90.796 120.406 329.482 0.000 19,760 | | 03BA 3380K 3880-23 VMBX57 20,055 14.88 5.63 26.42 83.804 140.338 305.811 0.000 20,055 | | 03F7 3390-2 3990-3 SAR104 52,419 12.34 14.67 8.41 194.028 134.251 112.446 0.000 52,419 | | 0641 3380D 3880-23 VMBX75 24,238 11.35 6.79 16.72 7.893 98.560 298.878 0.000 24,238 | | 0592 3380D 3880-23 VMBX11 11,950 8.19 3.35 24.46 2.779 60.539 229.023 0.000 11,950 | | 049A 3380K 3880-23 LIBP04 11,753 8.18 3.29 24.87 118.438 135.189 38.616 0.000 11,753 | | 03D0 3390-2 3990-3 SAR111 26,480 7.93 7.41 10.70 45.725 68.923 168.669 0.000 26,480 | | 0643 3380D 3880-23 VMBX76 6,096 5.87 1.71 34.37 5.461 98.202 105.867 0.000 6,096 | | 0597 3380D 3880-23 VMBX25 10,758 5.81 3.01 19.29 2.404 59.667 145.402 0.000 10,758 | | 0C47 CTCA 3088-04 87,252 3.97 24.43 1.63 4.234 66.146 71.527 0.000 87,252 | | | +----------------------------------------------------------------------------------------------------------------------------------+ Note: A volume with '@' by its VOLSER indicates a CSE shared device.
Figure 3-6. Detail VMX Device Ranking Report
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