Which command provides extended I/O statistics for storage devices, including utilization and wait time, with one‑step depth?

• A. iostat -xz 1
• B. iostat -x 1
• C. iostat -dx 1
• D. iostat -c 1

Answer: (A)

Extended I/O statistics at the device level come from the -x option in iostat, which reports utilization (how busy the device is) and the average wait time for I/O operations. To see these details for each storage device, you include device statistics, and using a filter like -z keeps the report focused by skipping devices with no activity. Setting the interval to one second makes the report update every second, providing a quick, stepwise view of activity.

So, iostat -xz 1 combines extended per-device statistics with a one-second sampling, and it omits idle devices for a concise, real-time view. Other options either miss the extended per-device data, don’t set the interval to one second, or show CPU statistics instead.