Display disk activity statistics with the sar -d command.
$ sar -d 00:00:00 device %busy avque r+w/s blks/s avwait avserv |
This abbreviated example illustrates the output from the sar -d command.
$ sar -d SunOS balmyday 5.10 s10_51 sun4u 03/18/2004 12:36:32 device %busy avque r+w/s blks/s avwait avserv 12:40:01 dad1 15 0.7 26 399 18.1 10.0 dad1,a 15 0.7 26 398 18.1 10.0 dad1,b 0 0.0 0 1 1.0 3.0 dad1,c 0 0.0 0 0 0.0 0.0 dad1,h 0 0.0 0 0 0.0 6.0 fd0 0 0.0 0 0 0.0 0.0 nfs1 0 0.0 0 0 0.0 0.0 nfs2 1 0.0 1 12 0.0 13.2 nfs3 0 0.0 0 2 0.0 1.9 nfs4 0 0.0 0 0 0.0 7.0 nfs5 0 0.0 0 0 0.0 57.1 nfs6 1 0.0 6 125 4.3 3.2 nfs7 0 0.0 0 0 0.0 6.0 sd1 0 0.0 0 0 0.0 5.4 ohci0,bu 0 0.0 0 0 0.0 0.0 ohci0,ct 0 0.0 0 0 0.0 0.0 ohci0,in 0 0.0 7 0 0.0 0.0 ohci0,is 0 0.0 0 0 0.0 0.0 ohci0,to 0 0.0 7 0 0.0 0.0 |
The following table describes the disk device activities that are reported by the -d option.
Field Name |
Description |
---|---|
device |
Name of the disk device that is being monitored. |
%busy |
Portion of time the device was busy servicing a transfer request. |
avque |
Average number of requests during the time the device was busy servicing a transfer request. |
r+w/s |
Number of read-and-write transfers to the device, per second. |
blks/s |
Number of 512-byte blocks that are transferred to the device, per second. |
avwait |
Average time, in milliseconds, that transfer requests wait idly in the queue. This time is measured only when the queue is occupied. |
avserv |
Average time, in milliseconds, for a transfer request to be completed by the device. For disks, this value includes seek times, rotational latency times, and data transfer times. |
Note that queue lengths and wait times are measured when something is in the queue. If %busy is small, large queues and service times probably represent the periodic efforts by the system to ensure that altered blocks are promptly written to the disk.