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
  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 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
  
• Only the local disk devices of Persistent DSF are collected in HP-UX 11i v3 (IPF).

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

None

None

• Fixed portion: 1,069 bytes
• Variable portion: 0 bytes

PFM-View name (PFM-Manager name)	Description	Smry	Format	Delta	Not sprtd in	Data 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.	AVG	utime	No	--	TOTAL_SERVICE_TIME DEVICE_COUNT
Avg Service Time/op(AVG_SERVICE_TIME)	Average I/O service time for a device (seconds)	AVG	utime	No	--	TOTAL_SERVICE_TIME 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.	%	float	No	--	((TOTAL_BUSY_TIME INTERVAL) DEVICE_COUNT) 100
Devices(DEVICE_COUNT)	Device count	AVG	ulong	No	--	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)	AVG	double	Yes	--	--
Interval(INTERVAL)	Interval at which the Device Summary (PI_DEVS) 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	sum-of-queue-lengths-of-all-devices DEVICE_COUNT
Read Ops %(READ_OPS_PERCENT)	Read operations as a percentage of all I/O operations (%)	%	float	No	HP-UX, AIX	TOTAL_READ_OPS TOTAL_IO_OPS 100
Reads(TOTAL_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	TOTAL_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 DEVS.	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 Devices when processes are continuously executed on a device.	AVG	utime	Yes	--	--
Total I/O Ops(TOTAL_IO_OPS)	Number of I/O operations that occurred	AVG	ulong	Yes	--	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)	R	float	Yes	--	TOTAL_IO_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 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.	AVG	utime	Yes	--	--
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.	AVG	utime	Yes	AIX	--
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 Devices when processes are continuously executed on a device.	AVG	utime	Yes	AIX	--
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.	AVG	utime	No	AIX	TOTAL_WAIT_LEN_TIME 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.	AVG	utime	No	AIX	TOTAL_WAIT_TIME DEVICE_COUNT
Write Ops %(WRITE_OPS_PERCENT)	Write operations as a percentage of all I/O operations (%)	%	float	No	HP-UX, AIX	TOTAL_WRITE_OPS TOTAL_IO_OPS 100
Writes(TOTAL_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	TOTAL_WRITE_OPS INTERVAL

Legend:

Smry: Summary

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