System Recovery

[Ben Scott]

On Tue, Jul 15, 2008 at 11:12 AM, Labitt, Bruce
<labittb1 at tycoelectronics.com> wrote:
> Thanks Jarod.  Hmm, I only have a 5.1 DVD right now.  Will that work?

  It should.  The on-disk filesystem format is the same.

  I would definitely recommned booting from external media (DVD) and
checking *all* the filesystems.  There may be undetected corruption
elsewhere on your disk.  And you can't check the root filesystem of
the running system.

  Initially, I would suggest "fsck -vfn" to see what the damage is
like.  Omit -c (badblocks) for now, that slows things considerably.

  Be sure to specific the actual device name, not the filesystem mount
point.  In other words, something like "fsck -vfn /dev/sda1" or
whatever.

On Tue, Jul 15, 2008 at 11:05 AM, Labitt, Bruce
<labittb1 at tycoelectronics.com> wrote:
> Attempt to read block from filesystem resulted in short read while
> trying to open /var.

  "short read" means fsck did a read()/fread() call for some number of
bytes, but the kernel returned a smaller number of bytes.  For
example, maybe fsck attempt to read the the superblock (4096 bytes),
but the kernel returned zero bytes.  Causes of this that I've seen
include:

(1) Bad hardware.  fsck requests a block, disk doesn't work, so kernel
returns zero bytes to calling program.  Check the kernel log (output
of "dmesg") for clues.
(2) Software bug in a disk controller driver.  Basically the same as 1.
(3) Severe filesystem corruption, such that the filesystem's data
structures point to locations past the end of the actual disk.

-- Ben