External USB HDD connected to RPi 3B +

Hi All, I want connect 2 USB HDD to my RPi 3B+.

I always have 1 HDD connected throuth USB and it receive power from RPi.

I want connect another one USB HDD (powered throuth its external cable and not throuth RPi).


  1. When I turn on the RPi, I don’t want to automatically start the second HDD.
  2. How could I mount and dismount the HDD throuth terminal?

Thanks a lot.

“Start” as in spin up you will not be able top stop as long as the USB cable is connected (just keep your RPi running than that problem is solved

sudo umount /media/<Label of the partition> but that might not be possible if Kodi is accessing the drive at that time.

Probably there is a config boot file that I could set to not mount automatically the unity usb HDD.
How can I do it?


Could you shed some light why this unwanted?

But that will not stop the HDD to “start” it will just stop it from mounting!
To avoid automouting of just one of 2 drives you would have to reconfigure udisk.glue.
Alternative is to mount your fist disk via fstab and disable udisk-glue overall.

Ok! Thanks.
I have an rpi always on with an usb hdd. I thought to connect another unit and activate it when I want from the terminal. I don’t want to keep the second unit always on for electricity consumption. The problem could be that if the energy goes away and the RPi restart and the two HDD start, and I don’t need it. I want start one of this and if it is necessary I want start the second hdd through terminal.

A lot of the external USB hard drives will spin down on their own after a period of inactivity. Additionally OSMC issues a command to spin down the platter after 20 minutes of inactivity. These are both specific to the drive/USB adapter and may either not work, or work but not turn off or blink the activity LED like it might in a different OS (due to it being a spin down and not sleep). In any event, even if the drive stays spinning the power consumption of a driving spinning but not being accessed should be very low.

If I’ve understood correctly, there’s a one-line hack you can use to achieve this.

Hi, when I send the command “sudo umount /media/HDD” it working properly. How do I set the time for spin down? or is possible to spin down with fast command?

When I connect this USB HDD with Windows OS and I not use it for some minutes it spin down and led off. How could I have this function on RPi OSMC?


I have found this: http://guide.debianizzati.org/index.php/Hdparm

It is possible to change the spin down time but it would have no positive effect to do so. Having a short spindown is hard on the drive, saves an infinitesimal amount of energy, and can cause issues with built in power saving on some drives usb to sata adapters. What your seeing on windows is likely usb selective suspend and that is not something supported by the pi. There is a thread about this topic on this forum where I went back and forth on the spindown. After a bunch of research and testing with both a Seagate and WD drive I could not find settings for either that worked better than when I started.

Thanks. After umount command is not possible mount.
After umount the HDD makes no noise but led is on. OK! but is not possible mount. Why?

sudo mount /media/MyHDD
mount: can’t find /media/MyHDD in /etc/fstab

If I restart raspberry sudo reboot 0, it boot again!