When is a SMART test insufficient?

• A. When RAID controllers abstract drive access (lack direct SMART visibility).
• B. When SMART is enabled on all drives.
• C. When there is only a single drive in the array.
• D. When the system is powered off.

Answer: (A)

When you run SMART tests, you rely on direct visibility to each physical drive’s SMART data. If a RAID controller sits between the host and the disks and does not pass through those SMART attributes, the host sees only the logical array, not the individual drives. In that case, a SMART test performed from the host won’t reliably reflect the health of the physical drives, making SMART tests insufficient for diagnosing issues in that environment. To properly monitor health, use the RAID controller’s health tools or enable SMART passthrough if supported, so you can access per-drive SMART data. Enabling SMART on all drives, having only a single drive, or powering the system off do not address the visibility issue in a RAID configuration, which is why the abstraction scenario is the best answer.