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I'm using Lubuntu and have an external hard drive.

I would like to safely unmount the external hard drive.

Clicking the eject button in the file manager unmounts the drive, but does not power it down. (EDIT: Clicking on mount and then unplugging the drive means, at least on my machine, that the drive is still spinning when it's unplugged. This isn't good for the drive, so it's not good for my data!)

Naturally, 'umount' does not perform this function.

I can issue 'sudo hdparm -Y /dev/sdb', but this still leaves the drive's light on and I don't think it syncs the drive.

I seem to recall 'sudo sdparm --command=stop /dev/sdb' powering the drive down appropriately in the past, but this doesn't seem to be working now, and it's a mystery as to why the GUI doesn't have an option to do this.

Any suggestions?

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up vote 2 down vote accepted

I think udisks --detach [device] can help you.

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Brilliant! That worked right from the command line. – Richard May 9 '13 at 18:13

You can use Gnome Disk Utility (palimpsest) to power down hard drive. In Ubuntu Gnome it is available under hard drive context menu ("Safely remove ..." I guess).

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Didn't know that command/utility even existed. It worked perfectly, thank you. Wish I knew a set of command-line operations for achieving the same effect, but this will work for now. – Richard Feb 12 '12 at 20:47

Unmounting the drive is enough to sync it and to be safe in unplugging it, with the added advantage of being able to remount it, if you want.

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Disagree. Unmounting the drive does not power it down. The drive is still spinning. Unplugging the USB connection to the computer causes an unplanned power-down. This is not healthy for the drive. Therefore, this is not safe. – Richard Jan 27 '12 at 19:24

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