freebsd stable - Sep 2008 - UNEXPECTED SOFT UPDATE INCONSISTENCY; RUN fsck MANUALLY

Sep 21 08:57:54 belle fsck: /dev/ad4s1d: 1 DUP I=190
Sep 21 08:57:54 belle fsck: /dev/ad4s1d: UNEXPECTED SOFT UPDATE INCONSISTENCY;
RUN fsck MANUALLY.

Ok, so I ran fsck manually (even with -y), but yet it refuses to clear/fix
whatever to the questions posed as fsck runs.  What does this all mean?

Thanks,

-Clint

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On Sun, Sep 21, 2008 at 02:34:26PM -0700, Clint Olsen
wrote:
> Sep 21 08:57:54 belle fsck: /dev/ad4s1d: 1 DUP I=190
> Sep 21 08:57:54 belle fsck: /dev/ad4s1d: UNEXPECTED SOFT UPDATE
INCONSISTENCY; RUN fsck MANUALLY.
> 
> Ok, so I ran fsck manually (even with -y), but yet it refuses to clear/fix
> whatever to the questions posed as fsck runs.  What does this all mean?
Are you running fsck on the filesystem while its mounted?  Are you doing
this in single-user or multi-user mode?

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |

On Sun, Sep 21, 2008 at 02:59:30PM -0700, Clint Olsen
wrote:
> I ran in multi-user mode because the system booted.  I figured that it
> would have halted the boot if it was serious enough to warrant single-user
> mode fsck.  That has happened before.
> 
> Thanks,
>
> -Clint
> 
> On Sep 21, Jeremy Chadwick wrote:
> > Are you running fsck on the filesystem while its mounted?  Are you
doing
> > this in single-user or multi-user mode?
Re-adding mailing list to the CC list.

No, I don't think that is the case, assuming the filesystems are UFS2
and are using softupdates.  When booting multi-user, fsck is run in the
background, meaning the system is fully up + usable even before the fsck
has started.

Consider using background_fsck="no" in /etc/rc.conf if you prefer the
old behaviour.  Otherwise, boot single-user then do the fsck.

You could also consider using clri(8) to clear the inode (190).  Do this
in single-user while the filesystem is not mounted.  After using clri,
run fsck a couple times.

Also, are there any kernel messages about ATA/SCSI disk errors or other
anomalies?

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |

Jeremy Chadwick wrote:
> I believe we're in overall agreement with regards to background_fsck
> (should be disabled by default).
In fact background fsck has been introduced for a good reason:
waiting for a full fsck on modern big disks is far too long.
Similarly write cache is enabled on ata disks for the reason that
without it performance sucks too much. My humble opinion is that you
attach far far too much importance to reliability in this game.
There are many reasons why corruption may happen in the files, most
of them being hardware related (bad ram, overheating chipset, etc.)
Hence you can never be assured that your data is perfectly reliable
(except perhaps ZFS permanent checksumming), all you have is some
probability of reliability. I think that for most people what is
important is a good balance between the risk of catastrophic failure
(which is always here, and is increased little by background fsck)
and the performance and ease of use. The FreeBSD developers have
chosen this middle ground, with good reason, in my opinion. People
who are more concerned with the reliability of their data, and
want to pay the price can always disable background fsck, maintain
backups, etc. Personnally i would run away from a system requiring
hours of fsck before being able to run multiuser. Neither Windows,
with NTFS, nor Linux, with ext3, reiserfs, xfs, jfs, etc. require
any form of scandisk or fsck. Demanding that full fsck is the default in
FreeBSD is akin to alienating a large fraction of users who have greener
pasture easily available. Idem for asking to disable write caching on
the disks. So for most people there is a probability to get some day
the UNEXPECTED SOFT UPDATE INCONSISTENCY message. They will run a full
fsck in that occasion, not a terrible thing. In many years of FreeBSD
use, it happened me a small number of times, and i have still to loose
a file, at least that i remarked.

-- 

Michel TALON