Device Detail (PI_DEVD)

Function

The Device Detail (PI_DEVD) record stores the performance data per unit time on the local disk device usage. Every time performance data is collected, a record is created for each local disk device. This is a multi-instance record.

Notes:
  • To collect the Device Detail (PI_DEVD) record in AIX, execute the smitty chgsys command and set Continuously maintain DISK I/O history to true.
  • In AIX, performance data of devices whose device names begin with vscsi or vhost is not collected.
  • In Linux, the performance data of block devices whose major numbers and block information are specified in the following file is collected from /proc/partitions and stored in the Device Detail (PI_DEVD) record.
    [Figure]Linux 6:/usr/share/doc/MAKEDEV-3.24/devices-2.6+.txt
  • 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.
  • In HP-UX 11i V3 (IPF), the local disk device of Legacy DSF and Persistent DSF both are collected.

Default values and values that can be specified

ItemDefault valueModifiable
Collection Interval60Yes
Collection Offset#0Yes
LogNoYes
LOGIFBlankYes
#
A value between 0 and 32,767 seconds can be specified (a value within the range specified for Collection Interval). Use this item to distribute the collection load, because executing data collection all at once results in concentration of the processing workload. Note that the data collection duration to be recorded is the same as the Collection Interval, regardless of the value specified for Collection Offset.
When changing the Collection Offset value, specify a value that takes into account the impact of the collection processing load.

ODBC key fields

PI_DEVD_DEVICE_NAME

Lifetime

None

Record size

Fields

PFM-View name
(PFM-Manager name)
DescriptionSmryFormatDeltaNot sprtd inData source
Avg Service Time(AVG_SERVICE_TIME)Average I/O service time for devices (seconds)AVGutimeNo--TOTAL_SERVICE_TIME [Figure] TOTAL_OPS
Avg Wait Time(AVG_WAIT_TIME)Average I/O wait time for devices (seconds)AVGutimeNoAIXTOTAL_WAIT_TIME [Figure] TOTAL_OPS
Busy %(BUSY_PERCENT)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] 100
Device Name(DEVICE_NAME)Device nameCOPYstring(40)No----
Device Type(DEVICE_TYPE)Device type. Disk (disk device) or Tape (tape device)COPYstring(5)No----
I/O Mbytes(TOTAL_IO_MBYTES)Total size of data transferred through I/O operations (MB)AVGfloatYes----
Interval(INTERVAL)Interval at which the Device Detail (PI_DEVD) 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 queueAVGulongNoAIX--
Read %(READ_OPS_PERCENT)Read operations as a percentage of all I/O operations (%)%floatNoHP-UX,
AIX
READ_OPS [Figure] (READ_OPS + WRITE_OPS) [Figure] 100
Read Mbytes(TOTAL_READ_MBYTES)Size of data transferred in read operations (MB)AVGfloatYesHP-UX--
Read Ops(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
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 DEVD.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 when processes are continuously executed on a device.
AVGutimeYes----
Total I/O Ops(TOTAL_OPS)Number of I/O operations that occurredAVGulongYes----
Total I/O Ops/sec(TOTAL_OPS_PER_SECOND)Frequency at which I/O operations occurred (number of I/O operations per second)RfloatYes--TOTAL_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 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 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 when processes are continuously executed on a device.AVGutimeYesAIX--
Wait Length Time(WAIT_LEN_TIME)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--
Write %(WRITE_OPS_PERCENT)Write operations as a percentage of all I/O operations (%)%floatNoHP-UX,
AIX
WRITE_OPS [Figure] (READ_OPS + WRITE_OPS) [Figure] 100
Write Mbytes(TOTAL_WRITE_MBYTES)Size of data transferred in write operations (MB)AVGfloatYesHP-UX--
Write Ops(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
WRITE_OPS [Figure] INTERVAL
Legend:
Smry: Summary
Not sprtd in: Not supported in