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Re: unmount on shutdown

On Fri, Mar 18, 2011 at 11:01 AM, Geoffrey Smith <gps@asu.edu> wrote:
> Hello, I am using Debian 6.0 Squeeze and the Gnome desktop on a typical
> desktop computer.  Suppose I have a USB drive mounted on /media/ and I do a
> normal shutdown via Gnome.  Is the USB drive automatically unmounted as part
> of the normal shutdown process?  The reason I ask is because I forgot to run
> umount before shutting down.  Thank you.  Geoff

For a little more explanation, if you shut down some
awkward/unexpected/exceptional way, such as a power blackout or a
cleaning staff mis-operation of the power outlets (well known
example!) or (ahem) when your 6-year-old son figures out that the
power switch on the back does something, there is a possibility that
dirty caches may not have been written to the disks before the DC
power from the PS module drops.

With modern file systems, which regularly write out their dirty caches
(sync, or something similar), this is less likely than, say, fifteen
years ago. But it is still possible.

One of the primary purposes of the normal shutdown procedures is to
sync and umount all the mounted volumes. (Orderly shutdown.) So, if
you use the GUI shutdown button (as you did), or the "shutdown"
command, you're golden.

Some of the other techniques may or may not sync and umount, but you
probably don't use those.

(Under Fedora, I have an SD card drive that, when I umount it, the
in-use light does not go out, so I actually power the machine down
before I remove it, to be safe. I'd check to see if it's the same in
Debian, but the camera's in a different room, and I don't want to have
to power down right now. And it occurs to me now, that I haven't tried
the safe un-mount option from the GUI with that drive.)

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