Practice

The given example shows disk activity statistics with the SAR -d command

# SAR -d 22

17:57:14          device  %busy avque   r+w/s   blks/s   avwait avserv (-d)

17:57:16                                                                                 

17:57:18          wd-0    0.50     1.00     1.00     1.99     0.00     5.00

Average           wd-0    0.25     1.00     0.50     1.00     0.00     5.00

In the above example, devices represent the name of the disk device being mounted. %busy denotes the percentage of time the device has spent in servicing a tranfer request. The avque specify the sum of the average wait time plus average service time. Here r+w/s display the number of read and write transfers to the device per second and blks/s denotes the number of 512-byte blocks transferred to the device per second. avwait denotes the average time in milliseconds which transfer to the device per second. avserv denotes the average time in milliseconds, for a transfer request to be done by the device (for disk). pwrite/s displays the average number of physical write requests, per second by using character device interfaces.