What command enables SMART on a Linux disk?

• A. sudo smartctl -s on /dev/sdX
• B. sudo smartctl -s off /dev/sdX
• C. sudo smartctl -i /dev/sdX
• D. sudo smartctl -H /dev/sdX

Answer: (D)

SMART management with smartctl is about both enabling and verifying SMART reporting on a drive. The option that shows the disk’s SMART health status for /dev/sdX is the one you use to verify that SMART reporting is active and functioning. Running this command reveals the current health and whether SMART data is being read from the device, which is typically the practical step you take after enabling SMART to confirm it’s indeed on and reporting correctly. The other actions are different: turning SMART on or off is done with a separate flag, querying basic device information is done with an information flag, and the health status flag specifically checks the health readout. In practice, this health-check command is what you use to confirm SMART is enabled and productive on the drive.