Viewing AIO activity

If applications are using asynchronous I/O
(AIO) to disk, you can use the -O option to
sar(ADM) (or mpsar(ADM) for SMP) to examine the performance of AIO requests. The values reported include the number of AIO read and write requests per second, and the total number of 1KB blocks (both read and write) being handled per second.
The %direct column of the report shows the percentage of AIO requests that are passed directly to the disk driver by the

POSIX.1b aio functions defined in the Software Update for Database Systems (SUDS) library. Other AIO requests are handled by the aio(HW) driver.