On Sun, 03 Aug 2014 22:08:59 +0200 Michael Biebl <bi...@debian.org>
wrote:
> Control: -1 important
>
> Am 03.08.2014 12:21, schrieb Tony Green:
> > Since my machine recently updated to using systemd, I have
experienced a number
> > of occasions when it would just hang at a blank screen when
booting.
> >
> > After some searching I managed to work out how to get back to
having verbose
> > output during the boot process, which showed me that the system
was refusing to
> > initialise because filesystems specified in /etc/fstab were not
available
> > (either NFS filesystems, when my network was playing up, or a USB
external
> > drive which had not spun up fast enough).
> >
> > It seems that systemd regards ANY missing filesystem as being a
fatal error,
> > whether or not that filesystem is actually essential to the boot
process.
> > Although this is certainly valid if vital partitions such as / or
/usr can't be
> > mounted, it's unhelpful for NFS or external partitions.
>
> [snip]
>
> > As a workaround, I have been able to ensure my system boots OK if
any of these
> > filesystems can't be mounted by adding "noauto" to /etc/fstab and
then mounting
> > the filesystems via /etc/rc.local instead.
>
> The better alternative in your case (i.e. mount if available but
don't
> fail otherwise) is to mark the file systems as "nofail". See man
fstab.
With mountall/Upstart, there is a nobootwait option supported. I
believe the behavior is similar to nofail, except that mountall will
emit the filesystem event before finishing mounting the filesystem as
well as not GAF about success/failure. Do you know if systemd supports
this? To implement this in systemd I believe you would make the
generator for mount units from fstab not add Before=local-fs.target or
Before=remote-fs.target if the nobootwait option is used. This solves
the problem that systemd does not know which filesystems are essential
or not.
Best wishes,
--
Cameron Norman
