Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 12 Dec 2017 20:01:26 +0100
From:      Polytropon <freebsd@edvax.de>
To:        freebsd@dreamchaser.org
Cc:        Adam Vande More <amvandemore@gmail.com>, FreeBSD Questions <freebsd-questions@freebsd.org>
Subject:   Re: Subject: Thunderbird causing system crash, need guidance
Message-ID:  <20171212200126.3ddf75e5.freebsd@edvax.de>
In-Reply-To: <5fbcd05c-ce12-b1a4-a9e9-79276dad7183@dreamchaser.org>
References:  <201712110045.vBB0jCTQ078476@nightmare.dreamchaser.org> <CA+tpaK0sG31TckxL8orNmAD0ZXSz7rJzEotjsCEtASw9u2COZg@mail.gmail.com> <38e2ef70-fa1b-25bf-4447-752006418d0a@dreamchaser.org> <20171211135803.d1aff6c8.freebsd@edvax.de> <5fbcd05c-ce12-b1a4-a9e9-79276dad7183@dreamchaser.org>

Next in thread | Previous in thread | Raw E-Mail | Index | Archive | Help
On Tue, 12 Dec 2017 11:30:26 -0700, Gary Aitken wrote:
> On 12/11/17 05:58, Polytropon wrote:
> > On Sun, 10 Dec 2017 21:56:16 -0700, Gary Aitken wrote:
> >> On 12/10/17 19:02, Adam Vande More wrote:
> >>> On Sun, Dec 10, 2017 at 6:45 PM, Gary Aitken wrote:
>   <snip>
> >> However, I'm confused.
> >> Upon reboot, the system checks to see if file systems were properly
> >> dismounted and is supposed to do an fsck.  Since those don't show up
> >> in messages, I can't verify this, but I'm pretty certain it must have
> >> thought it was clean, which it wasn't.  (One reason I'm pretty certain
> >> is the time involved when run manually as you suggested).
> > 
> > This is the primary reason for setting
> > 
> > 	background_fsck="NO"
> 
> Already had that set for just that reason.
> 
> > in /etc/rc.conf - if you can afford a little downtime.
> > The background fsck doesn't have all the repair capabilities
> > a forced foreground check has, to it _might_ leave the file
> > system in an inconsistent state, and the system runs with
> > that unclean partition.
> > 
> >> The file system in question was mounted below "/".
> >> Does the system only auto-check file systems mounted at "/"?
> > 
> > Yes, / is the first file system it checks. The two last
> > fields in /etc/fstab control what fsck will check, and
> > /etc/rc.conf allows additional flags for those automatic
> > checks.
> 
> The ordering part I understand; what I don't understand is why it (as I
> recall) rebooted successfully with no warnings in spite of the
> background_fsck="NO" being set and when one of the disks apparently
> didn't fsck properly.  I thought it should have halted in single-user
> mode and waited for me to do a full fsck manually.  Unfortunately, the
> fsck output is not printed to the log, and I logged in as root on the vt0
> device, so it had scrolled off by the time I went to look for it.  A
> good reason never to log into the vt0 device.  Is there any way to get
> the "transient" boot-time fsck and other messages recorded in the log?

There is an easy explanation:

The foregroud fsck at boot time can only handle a subset of
damages. In some cases, you are required to perform a second
run of fsck in order to fix problems. This is where a forced
full fsck is very useful (usually in single-user mode).

You can specify additional flags for boot-time fsck via
/etc/rc.conf, which are:

fsck_y_enable="NO"      # Set to YES to do fsck -y if the initial preen fails.
fsck_y_flags=""         # Additional flags for fsck -y
background_fsck="YES"   # Attempt to run fsck in the background where possible.
background_fsck_delay="60" # Time to wait (seconds) before starting the fsck.

For example, fsck_y_flags="-f" would be such an addition.
As you can see, an initial preen ("limited fsck") can fail,
and the filesystem might be in an inconsistent state. This
is probably what you've been experiencing.

See "man fsck" for details. :-)



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...



Want to link to this message? Use this URL: <http://docs.FreeBSD.org/cgi/mid.cgi?20171212200126.3ddf75e5.freebsd>