I'm using Linux Ubuntu 20.04 with HWE. I have two HDDs installed and those never go to sleep even if their usage is none for 5+ minutes (that's the setting in gnome Disks manager).

This used to work some time ago, but now doesn't seem to. If I manually put both disks to sleep, those stay as such for hours, so not quite sure what's preventing this from happening.

How can I find this out?



fuser and/or lsof don't report of any file open on those mounts (i.e. /disk2 and /disk6) - I've set the timer to 5 minutes, from 10 and I'll report what happens.

  • Check out this post for possible causes.
    – harrymc
    Sep 4, 2021 at 16:40
  • my smartd should be setup with default values (30 mins) and my disks are supposed to shutdown in 5 minutes of not being active. Checked the -B option and those don't support APM, not sure how to check -S via command line, but via Ubuntu UI it's 5 minutes... so not sure what's the issue.
    – Emanuele
    Sep 4, 2021 at 22:38
  • Does this happen if you just disable smartd?
    – harrymc
    Sep 5, 2021 at 8:35
  • I issued sudo smartd stop and waited approx 3 hours. The disks are still active/idle. Should I have used another command to stop smartd?
    – Emanuele
    Sep 5, 2021 at 16:12
  • Try service smartd stop.
    – harrymc
    Sep 5, 2021 at 16:42

1 Answer 1


Apart monitoring the filesystem with obvious tools such as fuser and lsof, the only tool which actually reports every activity is auditd (installing then issuing sudo auditctl -w /dev/sda -p rwa and then searching the logs with sudo ausearch -f /dev/sda).

With this powerful tool, one is able to clearly identify what is interacting with the given device (/dev/sda in this example) and then take appropriate actions.

In my case it's the combination of having a couple of WD disks which apparently don't play nice with with standby command and are woken up by the udisks2/udisksd daemon invoking the smart report command every 10 minutes (it shouldn't wake up the disk - or better preventing from standby-ing but it does with those WD here and here for more details).

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