Re: iotop - or, checking what is accessing a drive
On Fri 22 Mar 2019 at 16:16:51 (-0400), deb wrote:
> On 3/22/19 4:00 PM, David Wright wrote:
> > On Fri 22 Mar 2019 at 14:00:24 (-0400), deb wrote:
> > > On 3/22/19 1:48 PM, Curt wrote:
> > > > On 2019-03-22, deb <deb@rangingthoughts.org> wrote:
> > > > > > Depending on what's on the disk, it might be more useful to just use
> > > > > > lsof to see what files are open and try to understand what those might
> > > > > > be doing.
> > > > I believe you said that the external USB drive's LED remains on, even
> > > > after unmounting, and that indicates to you that there's activity on the
> > > > drive. I've always labored under the idea that a *flashing* light
> > > > indicated activity and a steady one an idle state.
> > > >
> > > > Now it occurs to me that these signal indications may depend on the make
> > > > and model of the drive itself.
> > > >
> > > > What should be the behavior of the LED on your drive when the drive is
> > > > unmounted and/or inactive?
> > > YES -- this differs by manufacturer.
> > … and by model, in the case of Seagate.
> >
> > > Just a reminder -- the bulk of mine are Seagate Backup Plus (1-5TB.
> > > USB 3.0).
> > > On Windows, when you dismount (Safely Remove) these
> > > the light goes off.
> > I've never seen the light go off until it spins down (those that do).
> >
> > > It is On when connected and very dimmly flashed when being accessed.
> > > So, it can flash a bit when indexes are up[dated,
> > > or a file is flushed -- and go right back to steady on.
> > My 5TB doesn't ever flash or dim; a little annoying.
> >
> > > I only *feel* safe, pulling the cable when the light is OFF.
> > If you're really worried, first remount the partitions readonly, which
> > will fail if they're in use. Then unmount them and disconnect.
>
> Good idea David.
>
> I'll add this to the list.
It was only a recommendation for yourself.
> by-the-by, (when I last checked) Windows does NOT have a mount
> read-only notion.
>
> The recommended approach when I last looked was to rip through each
> file and folder setting them individually to read-only.
>
> Guess how long that takes on a 5TB?
>
> Now multiply that guess by an office of drives; with people wanting to
> switch them back and forth R-O -> W -> R-O
One would presumably be expected to script it if there's no
equivalent of chmod -R. But I have no idea whether the semantics
of write-protected directories is the same in Windows as it is
in linux, and particularly for NTFS which I only ever mount RO.
> > > Again, I can NOT suffer a data-loss-because-of-Evil-Linux situation,
> > > giving the Windows-folk ammo.
> > Disks occasionally fail for everyone, irrespective of OS.
> >
> > > I wanted to switch to your name in the Subject Curt,
> > > but Jim P. will yell at me. :-)
> > >
> > >
> > > Screw it --- I switched it anyway.
> > I can already see whose post yours is commenting on. The rule is simple:
> > Change the subject line if the subject changes,
> > Don't change the subject line if the subject doesn't change.
>
> Ack on the subject-line change.
>
> I am one-time switching this one's back.
>
>
> Now then -- where ARE these rules?
>
> I'd like to hand a list to new users.
>
> Obviously, I don't know them all.
The more important ones are at https://www.debian.org/MailingLists/
Otherwise, "When in Rome" generally works best. That's why most
people lurk a while before they first post to a new list.
(That's not meant personally.)
> > On a technical point, there are those whose less functional
> > mail clients thread by subject line rather than Message-ID.
> > Their threading get totally fragmented by all your changes.
Cheers,
David.
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