Re: iotop - or, checking what is accessing a drive

[David Wright <deblis@lionunicorn.co.uk>]

On Fri 22 Mar 2019 at 21:19:19 (-0400), deb wrote:
> On 3/22/19 7:39 PM, Michael Stone wrote:
> > On Fri, Mar 22, 2019 at 04:23:32PM -0400, deb wrote:
> > > On 3/22/19 4:07 PM, Michael Stone wrote:
> > > > On Fri, Mar 22, 2019 at 03:00:23PM -0500, David Wright wrote:
> > > > > If you're really worried, first remount the partitions readonly, which
> > > > > will fail if they're in use. Then unmount them and disconnect.
> > > > 
> > > > Just unmount--that will fail if the partition is in use
> > > > unless extra options are added.
> > > 
> > > Actually no.
> > 
> > Actually, yes.
> > > That's where I started at.
> > > 
> > > A given drive should behave the same on Windows & Linux as far
> > > as lights on/off/dimming.

I don't think the difference is in the behaviour of the drive, but in
the behaviour of whatever it's plugged into.

> > > But as I noted earlier, on Windows, the light is OFF,
> > > signaling no drive activity upon being removed.
> > > 
> > > On debian 9.8, it stays on, after repeated dismounts.

Yes. Presumably you had to mount it between each dismount.
(You can't unmount something that's not mounted.)

In Windows, after you have Safely Removed the drive with the menu,
try leaving the drive plugged in. Now mount it again. Can you?
You could in linux.

> > Then there's nothing using the drive and you're barking up the
> > wrong tree.
> > 
> > What you're seeing is that windows does a disconnect if you're
> > using the "safely remove" thing. You might be able to get the same
> > effect in linux by running "eject" on the drive, depends on what
> > specifically the drive is looking for.
> 
> I had previously tried eject as well.
> 
> Hard light was still on.
> 
> My choice was shutdown and pull the cable or pull it out seemingly hot.

Is that a problem? USB was designed for hot plugging and unplugging.
In fact, some systems won't recognise that a device is present unless
it is plugged in hot, eg my AiO Printer.

> Hopefully the tool choices from the others will provide info.

If those tools are looking for activity, they won't find any.

Cheers,
David.