[kwlug-disc] powering Seagate USB external disk off and on from Linux?

[Raymond Chen]

Is your external HDS in an enclosure with a power adapter? I would plug it
into a smart plug and use an app or a script to call an API to turn it
on/off.

On Mon, Nov 17, 2025 at 18:59 D. Hugh Redelmeier <hugh at mimosa.com> wrote:

> I want to use a cheap external HDD for backups.  I want the drive to be
> off when not in use but I don't want to be required to plug or unplug the
> drive to turn it on.
>
> Is there a way for a script to turn off a disk so it really is off enough
> and subsequently turn it on again?
>
>
> - consumer HDDs have ridiculously low power-on lifetimes, at least
>   according to their specifications
>
> - so I want my backup software to power the drive on before use and
>   off after use.
>
> - [may be relevant] Seagate external drive controllers have a flaw: to be
>   fast, you want to use UAS (USB Attached SCSI) but the controller won't
>   pass SAT commands in this mode.  You need to tell the driver that the
>   drive has a "quirk" to lock in usb-storage mode.
>   <https://www.smartmontools.org/wiki/SAT-with-UAS-Linux>
>
> Just unmounting all partitions of an HDD does not seem to cause it to spin
> down.  The drive still makes noise and is warm, even hours later.
>
> Turning off the drive, using Gnome's Disks or (untested) udisksctl(1),
> does stop the drive.  But I don't know how to subsequently turn it on via
> a program.  For example, Gnome Disks doesn't see the drive once it has
> been turned off.  The way I know to turn on the drive is to physically
> unplug the USB cable and plug it in again.
>
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