Display disk activity statistics with the sar -d command.
$ sar -d 00:00:00 device %busy avque r+w/s blks/s avwait avserv 01:00:00 fd0 0 0.0 0 0 0.0 0.0 |
The table below describes the disk devices activities reported by the -d option. Note that queue lengths and wait times are measured when there is something 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 written to the disk in a timely fashion.
Table 36-10 Output from the sar -d Command
Field Name |
Description |
---|---|
device |
Name of the disk device being monitored |
%busy |
Percentage of time the device spent servicing a transfer request |
avque |
The sum of the average wait time plus the average service time |
r+w/s |
Number of read and write transfers to the device per second |
blks/s |
Number of 512-byte blocks transferred to the device per second |
avwait |
Average time, in milliseconds, that transfer requests wait idly in the queue (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 includes seek, rotational latency, and data transfer times) |
This abbreviated example illustrates the sar -d output.
$ sar -d SunOS venus 5.8 Generic sun4u 09/07/99 00:00:00 device %busy avque r+w/s blks/s avwait avserv 01:00:00 fd0 0 0.0 0 0 0.0 0.0 nfs1 0 0.0 0 0 0.0 0.0 sd0 0 0.0 0 0 0.0 39.6 sd0,a 0 0.0 0 0 0.0 39.6 sd0,b 0 0.0 0 0 0.0 0.0 sd0,c 0 0.0 0 0 0.0 0.0 sd0,f 0 0.0 0 0 0.0 0.0 sd0,g 0 0.0 0 0 0.0 0.0 sd0,h 0 0.0 0 0 0.0 0.0 sd6 0 0.0 0 0 0.0 0.0 |