Re: [gentoo-user] Mysteriously dismounting partition

["J. Roeleveld" <joost@antarean.org>]

On Tuesday, October 27, 2015 12:25:07 PM Peter Humphrey wrote:
> On Tuesday 27 October 2015 12:04:46 Stefan G. Weichinger wrote:
> > Am 26.10.2015 um 15:47 schrieb Peter Humphrey:
> > > I keep the portage tree under /usr-bits.
> > > 
> > > # dmesg | grep sdb3
> > > [    1.753508]  sdb: sdb1 sdb2 sdb3 sdb4 < sdb5 sdb6 sdb7 sdb8 sdb9 >
> > > [    4.833460] EXT4-fs (sdb3): mounted filesystem with ordered data
> > > mode.
> > > Opts: (null)
> > > [  107.205918] EXT4-fs (sdb3): mounted filesystem with ordered data
> > > mode.
> > > Opts: (null)
> > > 
> > > You can see the successful mount at 4.8 s; the entry at 107 s is me
> > > mounting it again manually.
> > > 
> > > I've rewritten the partition label, and I've run a smartctl test which
> > > reported no faults found. I've also just reduced the speed of the
> > > chipset,
> > > which has three settings: good performance, better performance and
> > > turbo.
> > > It adopts the turbo setting by default and I've now set it to "better".
> > > It's too early yet to see if that will help.
> > 
> > interesting ...
> > 
> > What init-system? openrc or systemd?
> 
> Openrc.
> 
> > No trace of the actual unmount in any logs?
> 
> Not that I can find, no.
> 
> > Maybe also look/grep for the LABEL of the fs.
> 
> Nope, nor that.
> 
> > Maybe test if using the device-name itself ( /dev/sdb3 ) or the UUID in
> > fstab changes the behavior.
> 
> I'll try reverting to /dev/sdb3 and see if that helps.
> 
> > I use UUIDs here without problems (with systemd).
> 
> The only thing I use UUIDs for here is in mdadm.conf to get the LVs started
> reliably for the main system*. Those live in partitions /dev/sd[ab][5789].
> 
> Three more things: I've had the cover off and checked the seating of the
> SATA cables; while the lid was off I watched the MB LEDs during startup,
> which seemed okay; and today the kernel was upgraded from 4.0.5 to 4.0.9;
> that may help too. (Hm ... too many changes at once.)
> 
> * Now that I think of it, one of the LVs came up as inactive the other day,
> and nothing I could think of would activate it (consulting man mdadm of
> course). In the end I had to reboot. This machine has shown some bizarre
> behaviour over the last few months. Something is definitely wrong; I just
> can't figure out what it is.

The full log for that entire period might be useful.

If a disk is umounted/removed, something needs to be logged somewhere.
Might even be a comment from the scsi-subsystem or the SATA driver.

I usually only grep the log to try to find specific messages.
If I know the time-period something weird happened in, I tend to go through 
the unfiltered log for that period.

--
Joost