From: "Müller, Markus" <Markus.Mueller@itworks-gmbh.de>
> I never had to use fsck so I just want to know what exactly is it doing,
> how do I use it properly and could there be any serious problems - the
data
> on that disk are *crucial* for our work here (yes, we do have backups...).

fsck is pretty much "fire and forget".  It will go through the disk,
checking that all inodes are valid, verifying that files don't point to
blocks on the free space list, and fixing any errors it can.  If there are
any serious problems, fsck will prompt you for confirmation before it makes
any serious changes.  Unfortunately, unless you have a fair understanding of
the file system structures, it can be difficult to understand what fsck is
suggesting.

To use it, you first have to unmount the filesystem.  The command you want
is "fsck /dev/wd1a".  Once fsck is finished, just remount the disk.  If wd1a
is your root partition, you may have to drop into single-user mode.

Cheers!
-- Tracy Nelson