Is SMART disabled in all portable USB hard drives?

I own a few portable USB hard disk drives.

Recently after replacing my laptop's failing drive I was using GSmartControl (Linux) to access the SMART data on my disks, looks like all the external drives that have USB connectivity don't have SMART support.

I own 2 ADATA HD710 drives and a Western Digital MyBook 3 TB. All use USB 3.0 connectivity.

I use one ADATA drive for daily inceremental backups, and the 3 TB drive for only-copy of old data and backup disk images of my family's laptops etc.

I'm pretty sure the MyBook has a standard big SATA drive inside. Is exposing the SMART features not possible with a USB interface? Or is this something else?

On the other hand my SanDisk 32 GB USB 3.0 pendrive reports to be SMART-enabled (while displaying no data at all).

What's the matter? How do I know if my backup medium is in good shape if it won't even report bad blocks? Should I stop using USB drives for backups?

Answer

In Linux we have smartmontools. Its website gives the insight. The most important fragment:

To access SMART functionality, smartmontools must be able to send ATA commands directly to the disk. For USB devices, at least the following conditions must be met:

• The USB bridge provides an ATA pass-through command.


• This command is supported by smartmontools.


• The operating system provides a SCSI pass-through I/O-control which works through its USB-layer.


• SCSI support is implemented in the operating system interface of smartmontools.

Notice there are conditions independent of smartmontools. I guess the situation is similar with whatever tool you use.

I had two USB adapters and only one of them let me use SMART functionality (tested with one and the same HDD).