USB drives are notorious for hiding their SMART data behind finicky USB-to-SATA bridges. If you’ve ever tried to check the health of a Seagate USB drive and gotten frustrated with “unsupported field in scsi command” errors, you’re not alone.
After wrestling with several Seagate drives in my homelab, I finally figured out the magic incantations needed to get SMART data working. Here’s how to do it properly.
Update (2026-02-03): This article has been superseded by USB Drive SMART Updates: Fast-Track to the GRUB Solution which includes updated device IDs and production experience from my Ceph cluster deployment.
Note: The decision to not allow this in Linux as a default was done for good reasons. You are playing with fire as some drives behave erratically. I have not experienced this with recently purchased USB drives, but older ones did have quirks and issues. So buyer beware.