Practice

The given example display how to check buffer activity using SAR

# SAR-b 2 2

17:56:37 bread/s lread/s %rcache bwrit/s lwrit/s %wcache pread/s pwrit/s(-b)

17:56:39           0       2      100            8         2          0         0      0

17:56:41           2       0         0           0         0          0         0      0

Average            1      2        20            4         1         0          0      0

Here bread/s denotes the average number of reads per second submitted to the buffer cache from the disk.  lread/s denotes average number of  logical reads per  second from  the  buffer  cache.  %rcache denotes the fraction of logical writes found in the buffer cache (100 percent minus the ratio of bread/s to lread/s). The bwrite average number of physical blocks (512 blocks) written from the buffer cache to disk, per second. lwrite/s denotes the average number of logical writes to the buffer cache, per second. %wcache denotes the fraction of logical writes found in the buffer cache (100 percent minus the ratio of bwrite/s to lwrite/s). pread/s denotes the average number of physical reads, per second, using character device interface. pwrite/s denotes the average number of physical write requests, per second, using character device interfaces.