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I am running Kubuntu from External Hard Drive. My Internal Hard Drive has Windows on it. I don't want to use it while on Ubuntu and want to turn it off to produce less heat as well consume lower battery. I think spinning down hard drive isn't an option for me. Because, it wear out the hard drive and I don't plan to spend on HDD's :)

AhmedBilal
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3 Answers3

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sudo hdparm -Y /dev/sdX

where /dev/sdX is the device you'd like to turn off. You can also run sudo blkid to determine the device's 'fingerprint' (UUID), which would allow you to more reliably control which device is being turned off.

In this case, you'd run:

sudo hdparm -Y /dev/disk/by-uuid/DEVICE-IDENT-HERE

man hdparm

   -Y     Force  an  IDE  drive  to  immediately  enter  the  lowest power
          consumption sleep mode, causing it to shut down  completely.   A
          hard  or soft reset is required before the drive can be accessed
          again (the Linux IDE driver will automatically handle issuing  a
          reset  if/when  needed).   The  current power mode status can be
          checked using the -C option.
muru
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earthmeLon
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  • What exactly is `hard or soft reset`, i. e. how to get the drive back? – Asalle May 19 '19 at 18:18
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    This command did turn off the hard disk drive, but running `sudo hdparm -C /dev/sdX` to query the status will turn on the drive again then goes to stand by (a soft reset, I guess). Does the job for power saving, but not for simulating installation without the hard disk drive. –  Aug 04 '19 at 17:23
16

You likely have the udisks2 package installed; you can use 

udisksctl power-off -b /dev/sdX

where /dev/sdX is the device you'd like to turn off.

From udisksctl man page (version 2.7.6):

power-off
    Arranges for the drive to be safely removed and powered off. On the OS
    side this includes ensuring that no process is using the drive, then
    requesting that in-flight buffers and caches are committed to stable
    storage. The exact steps for powering off the drive depends on the
    drive itself and the interconnect used. For drives connected through
    USB, the effect is that the USB device will be deconfigured followed
    by disabling the upstream hub port it is connected to.

    Note that as some physical devices contain multiple drives (for
    example 4-in-1 flash card reader USB devices) powering off one drive
    may affect other drives. As such there are not a lot of guarantees
    associated with performing this action. Usually the effect is that the
    drive disappears as if it was unplugged.
Taylor R
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  • That works on Ubuntu 20.04. Is there a way to power on afterwards? – Sven Oct 13 '20 at 12:52
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    @Sven I believe that the poweroff command literally tells the hardware to power down, so it won't accept any commands after that point. You will likely need to power on your device manually after that; and that's likely device-dependent (disconnect / reconnect power supply, etc) – Taylor R Oct 13 '20 at 20:40
  • do you know natively on low level command what it actually does? sorry just for learning purpose – stackunderflow Jun 20 '21 at 16:11
  • I don't actually! – Taylor R Jun 21 '21 at 05:45
  • It seems the command works for USB drives only? I got "Error powering off drive: No usb device (udisks-error-quark, 0)" – Kenji Noguchi Jul 18 '22 at 05:59
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You can use the following (here sdc is the name of corresponding block device of interest):

sync
echo 1 > /sys/block/sdc/device/delete

or (from non-root user):

sync
echo 1 | sudo tee /sys/block/sdc/device/delete
Tomilov Anatoliy
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    +1 This works as expected to prevent the installer from detecting the hard disk drive at all. Must run the commands as root (not sudo). –  Aug 04 '19 at 17:15
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    I think the same is feasible using `sudo`: `sudo bash -c 'echo 1 > /sys/block/sdc/device/delete'`. – Tomilov Anatoliy Aug 05 '19 at 15:44
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    It worked perfectly for a Linux Mint 19.1 installation from a USB stick. – Matt Mello Jun 02 '20 at 23:01
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    This should be the accepted answer, because it works for any internal (e.g. SATA) and external (e.g. USB) HD (hard disk), SSD (solid state drive), flash drive (aka *pendrive*, aka *thumb drive*), SD card etc. – Yuri Sucupira Aug 27 '21 at 02:40
  • This did not actually power off my USB hard drive, just made it disappear from the system. The accepted answer with hdparm worked. – blade Aug 29 '22 at 08:06