[TriLUG] hard drive error; it wants the FSCK

[Jeremy Portzer]

On Fri, 2003-08-29 at 10:12, Douglas Kojetin wrote:
> hi all-
> 
> preface point #1: i've only run FSCK once, and it corrupted my entire 
> drive; i lost all data, therefore, i'm not looking forward to running 
> it again, but ....

Actually, you run fsck every time you start your system.  Normally it
does a very quick check, notices that your filesystem is "clean," and
continues.  Occasionally it will do a more in-depth check, after the
"maximum mount count" is reached.  This is part of the standard boot
process for any Linux system.

> preface point #2: this hard drive was in a box whose mobo had to be 
> replace (>10 capacitors blew)

I don't think that would be related, but who knows.

> one of my partitions (/misc; which happens to be an entire hard drive; 
> i think the drive is western digital) was giving an error about the 
> /misc partition when i tried to boot the computer and asked to run FSCK 
> or log in as root to remedy the issue.
> 
> to get around this, i logged in as root, commented out the /misc 
> partition from /etc/fstab, and it started just fine. but after booting, 
> i tried to uncomment and run 'mount -a', and got these errors:
> 
> -- from /var/log/messages (i think that was the log)
> Aug 26 15:47:17 dabox kernel: EXT3-fs error (device ide0(3,65)): 
> ext3_check_descriptors: Block bitmap for group 512 not in group (block 
> 22020176)!
> Aug 26 15:47:17 dabox kernel: EXT3-fs: group descriptors corrupted !
> Aug 26 15:47:24 dabox kernel: EXT3-fs error (device ide0(3,65)): 
> ext3_check_descriptors: Block bitmap for group 512 not in group (block 
> 22020176)!
> Aug 26 15:47:24 dabox kernel: EXT3-fs: group descriptors corrupted !
> 
> can anyone give me any advice on how to repair the disk/partition 
> without causing (or causing minimal) damage to the drive/partition?

Well, I don't know exactly what those errors mean.  But what I would
suggest doing is running "fsck /dev/[whatever]" from the command line
(with the partition unmounted).   The default flags should be fine -- it
will prompt you before doing anything that would result in lost data. 
Problem is, unless you're a filesystem guru, you normally have to accept
those prompts.

> what flags?  use a boot disk instead of a booted system?  anything else?

If the partition is unmounted you can run fsck from a fully running
system.  Only if that partition is required for running the system (like
/ or /usr ) do you need to worry about single-user mode or boot disks.

--Jeremy

-- 
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| Jeremy Portzer       jeremyp at pobox.com       trilug.org/~jeremy     |
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