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.
  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 type	Report type	Actions to be taken after modification
  Device	Real-time	Display the report again.
  	Historical	Specify 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:
  Interval (INTERVAL)
  Record Time (RECORD_TIME)
  Record Type (INPUT_RECORD_TYPE)
  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.

Item	Default value	Modifiable
Collection Interval	60	Yes
Collection Offset#	0	Yes
Log	No	Yes
LOGIF	Blank	Yes

#

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.

PI_DEVD_DEVICE_NAME

None

• Fixed portion: 681 bytes
• Variable portion: 405 bytes

PFM-View name (PFM-Manager name)	Description	Smry	Format	Delta	Not sprtd in	Data source
Avg Service Time(AVG_SERVICE_TIME)	Average I/O service time for devices (seconds)	AVG	utime	No	--	TOTAL_SERVICE_TIME TOTAL_OPS
Avg Wait Time(AVG_WAIT_TIME)	Average I/O wait time for devices (seconds)	AVG	utime	No	AIX	TOTAL_WAIT_TIME 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.	%	float	No	--	(TOTAL_BUSY_TIME INTERVAL) 100
Device Name(DEVICE_NAME)	Device name	COPY	string(40)	No	--	--
Device Type(DEVICE_TYPE)	Device type. Disk (disk device) or Tape (tape device)	COPY	string(5)	No	--	--
I/O Mbytes(TOTAL_IO_MBYTES)	Total size of data transferred through I/O operations (MB)	AVG	float	Yes	--	--
Interval(INTERVAL)	Interval at which the Device Detail (PI_DEVD) record was stored (seconds)	COPY	ulong	Yes	--	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)	R	float	Yes	--	TOTAL_IO_MBYTES INTERVAL
Queue Length(QUEUE_LENGTH)	Number of I/O requests in the device queue	AVG	ulong	No	AIX	--
Read %(READ_OPS_PERCENT)	Read operations as a percentage of all I/O operations (%)	%	float	No	HP-UX, AIX	READ_OPS (READ_OPS + WRITE_OPS) 100
Read Mbytes(TOTAL_READ_MBYTES)	Size of data transferred in read operations (MB)	AVG	float	Yes	HP-UX	--
Read Ops(READ_OPS)	Number of read operations that occurred	AVG	ulong	Yes	HP-UX, AIX	--
Reads/sec(READ_OPS_PER_SECOND)	Frequency at which read operations occurred (number of read operations per second)	R	float	Yes	HP-UX, AIX	READ_OPS INTERVAL
Record Time(RECORD_TIME)	Time at which the record was created (Greenwich Mean Time)	COPY	time_t	No	--	--
Record Type(INPUT_RECORD_TYPE)	Record type. Always DEVD.	COPY	char(8)	No	--	--
Seek Ops(SEEK_OPS)	Number of seek operations	AVG	ulong	Yes	Solaris, 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.	AVG	utime	Yes	--	--
Total I/O Ops(TOTAL_OPS)	Number of I/O operations that occurred	AVG	ulong	Yes	--	--
Total I/O Ops/sec(TOTAL_OPS_PER_SECOND)	Frequency at which I/O operations occurred (number of I/O operations per second)	R	float	Yes	--	TOTAL_OPS 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.	AVG	utime	Yes	--	--
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.	AVG	utime	Yes	AIX	--
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.	AVG	utime	Yes	AIX	--
Write %(WRITE_OPS_PERCENT)	Write operations as a percentage of all I/O operations (%)	%	float	No	HP-UX, AIX	WRITE_OPS (READ_OPS + WRITE_OPS) 100
Write Mbytes(TOTAL_WRITE_MBYTES)	Size of data transferred in write operations (MB)	AVG	float	Yes	HP-UX	--
Write Ops(WRITE_OPS)	Number of write operations that occurred	AVG	ulong	Yes	HP-UX, AIX	--
Writes/sec(WRITE_OPS_PER_SECOND)	Frequency at which write operations occurred (number of write operations per second)	R	float	Yes	HP-UX, AIX	WRITE_OPS INTERVAL

Legend:

Smry: Summary

Not sprtd in: Not supported in