Device Summary (PI_DEVS)

Function

The Device Summary (PI_DEVS) record stores the performance data in which the data stored in the Device Detail (PI_DEVD) record is summarized per unit time. Note that even if the Device Detail (PI_DEVD) record is not collected, performance data is stored in the Device Summary (PI_DEVS) record.

Notes:
  • To collect the Device Summary (PI_DEVS) record in AIX, execute the smitty chgsys command and set Continuously maintain DISK I/O history to true.
  • In Linux, the performance data of only the devices that have the following major numbers specified in the following file are collected from /proc/partitions and summarized in the Device Summary (PI_DEVS) record: 3, 8, 22, 33, 34, 56, 57, 65 to 71, 88 to 91, and 128 to 135
    [Figure]Linux 46: /usr/share/doc/MAKEDEV-3.24/devices-2.6+.txt
    For major numbers, see the block devices in the above file that match the contents of the Device Name (DEVICE_NAME) field.
  • If the DR function of Solaris 10 or later is used to modify a system resource while a PFM - Agent for Platform service is running, some types of performance data cannot be correctly collected. The table below shows the types of system resources that are affected and the actions that you can take to correctly display reports after the modification.
    System resource typeReport typeActions to be taken after modification
    DeviceReal-timeDisplay the report again.
    HistoricalSpecify the display period such that it does not include the date and time when the system resources were modified.
    Fields other than those listed below are affected by a system resource modification:
    [Figure]Interval (INTERVAL)
    [Figure]Record Time (RECORD_TIME)
    [Figure]Record Type (INPUT_RECORD_TYPE)
    [Figure]Fields that are added only when data is recorded in the Store database
    For details about modifying system resources, see Notes on performance information when modifying system resources in Notes on records
  • Only the local disk devices of Persistent DSF are collected in HP-UX 11i v3 (IPF).

Default values and values that can be specified

ItemDefault valueModifiable
Collection Interval60Yes
Collection Offset0Yes
LogNoYes
LOGIFBlankYes

ODBC key fields

None

Lifetime

None

Record size

Fields

PFM-View name
(PFM-Manager name)
DescriptionSmryFormatDeltaNot sprtd inData source
Avg Service Time/device(SERVICE_TIME)Average service time per device (seconds).
In HP-UX, this value indicates the total service time of all I/Os, and therefore, it may significantly exceed the value of Interval when processes are continuously executed on a device. Even with other OSs, the value may exceed the value of Interval when processes are continuously executed on a device.
AVGutimeNo--TOTAL_SERVICE_TIME [Figure] DEVICE_COUNT
Avg Service Time/op(AVG_SERVICE_TIME)Average I/O service time for a device (seconds)AVGutimeNo--TOTAL_SERVICE_TIME [Figure] TOTAL_IO_OPS
Busy %(BUSY_PERCENT)Average percentage of time a disk was busy (%).
This value may exceed 100 when processes are continuously executed on a device.
%floatNo--((TOTAL_BUSY_TIME [Figure] INTERVAL) [Figure] DEVICE_COUNT) [Figure] 100
Devices(DEVICE_COUNT)Device countAVGulongNo--Number of Device Detail (PI_DEVD) records of the category "disk" summarized in the Device Summary (PI_DEVS) record
I/O Mbytes(TOTAL_IO_MBYTES)Total size of data transferred through I/O operations (MB)AVGdoubleYes----
Interval(INTERVAL)Interval at which the Device Summary (PI_DEVS) record was stored (seconds)COPYulongYes--RECORD_TIME - previous-record-time; for real-time, RECORD_TIME - last-boot-time
Mbytes Xferd/sec(MBYTES_TRANSFERRED_PER_SECOND)Average I/O speed (MB per second)RfloatYes--TOTAL_IO_MBYTES [Figure] INTERVAL
Queue Length(QUEUE_LENGTH)Number of I/O requests in the device queueAVGulongNoAIXsum-of-queue-lengths-of-all-devices [Figure] DEVICE_COUNT
Read Ops %(READ_OPS_PERCENT)Read operations as a percentage of all I/O operations (%)%floatNoHP-UX,
AIX
TOTAL_READ_OPS [Figure] TOTAL_IO_OPS [Figure] 100
Reads(TOTAL_READ_OPS)Number of read operations that occurredAVGulongYesHP-UX,
AIX
--
Reads/sec(READ_OPS_PER_SECOND)Frequency at which read operations occurred (number of read operations per second)RfloatYesHP-UX,
AIX
TOTAL_READ_OPS [Figure] INTERVAL
Record Time(RECORD_TIME)Time at which the record was created (Greenwich Mean Time)COPYtime_tNo----
Record Type(INPUT_RECORD_TYPE)Record type. Always DEVS.COPYchar(8)No----
Seek Ops(SEEK_OPS)Number of seek operationsAVGulongYesSolaris,
AIX,
Linux
--
Total Busy Time(TOTAL_BUSY_TIME)Total busy time for a device (seconds).
This value may exceed the value of Interval [Figure] Devices when processes are continuously executed on a device.
AVGutimeYes----
Total I/O Ops(TOTAL_IO_OPS)Number of I/O operations that occurredAVGulongYes--TOTAL_READ_OPS + TOTAL_WRITE_OPS
Total I/O Ops/sec(TOTAL_OPS_PER_SECOND)Frequency at which I/O operations occurred (number of operations per second)RfloatYes--TOTAL_IO_OPS [Figure] INTERVAL
Total Service Time(TOTAL_SERVICE_TIME)Total service time for a device (seconds). This value includes wait time.
In HP-UX, this value indicates the total service time of all I/Os, and therefore, it may significantly exceed the value of Interval [Figure] Devices when processes are continuously executed on a device. Even with other OSs, the value may exceed the value of Interval when processes are continuously executed on a device.
AVGutimeYes----
Total Wait Length Time(TOTAL_WAIT_LEN_TIME)Total length of time I/Os waited for a device (seconds). The processing capacity of the I/Os that were waiting is divided by the I/Os' processing capacity per second, and is then integrated over the wait time.AVGutimeYesAIX--
Total Wait Time(TOTAL_WAIT_TIME)Total wait time for a device (seconds).
In HP-UX, this value indicates the total wait time of all I/Os, and therefore, it may significantly exceed the value of Interval [Figure] Devices when processes are continuously executed on a device.
AVGutimeYesAIX--
Wait Length Time(WAIT_LEN_TIME)Average length of time an I/O waited for a device (seconds). The processing capacity of the I/Os that were waiting is divided by the I/Os' processing capacity per second, is integrated over the wait time, and is then divided by the device count.AVGutimeNoAIXTOTAL_WAIT_LEN_TIME [Figure] DEVICE_COUNT
Wait Time(WAIT_TIME)Average wait time for a device (seconds).
In HP-UX, this value indicates the total wait time of all I/Os, and therefore, it may significantly exceed the value of Interval when processes are continuously executed on a device.
AVGutimeNoAIXTOTAL_WAIT_TIME [Figure] DEVICE_COUNT
Write Ops %(WRITE_OPS_PERCENT)Write operations as a percentage of all I/O operations (%)%floatNoHP-UX,
AIX
TOTAL_WRITE_OPS [Figure] TOTAL_IO_OPS [Figure] 100
Writes(TOTAL_WRITE_OPS)Number of write operations that occurredAVGulongYesHP-UX,
AIX
--
Writes/sec(WRITE_OPS_PER_SECOND)Frequency at which write operations occurred (number of write operations per second)RfloatYesHP-UX,
AIX
TOTAL_WRITE_OPS [Figure] INTERVAL
Legend:
Smry: Summary
Not sprtd in: Not supported in