[ILUG] Can an ILUG guru save me?

[Niall O Broin]

On 4 Mar 2005, at 21:16, Timothy Murphy wrote:

> The root partition (/dev/hda3) on my laptop
> is not longer recognised as a valid filesystem.
> (When I run "fsck /dev/hda3" from a rescue CD
> I am told "Could not determine filesystem type"
> while "e2fsck /dev/hda3" tells me
> "The superblock could not be read ...",
> and suggests I try an alternative superblock
> with "e2fsck -b 8193 /dev/hda3".
> However, this brings up the same message.
>
> Is there anything I can do short of re-installing the system 
> (Fedora-3)?

Restore from your backups?
>
> I thought there were lots of copies of the superblock,
> but how does one tell where they are?

One does    mke2fs -n <OPTIONS> /dev/hda3

where <OPTIONS> are the same options originally used to create the 
filesystem e.g. -m, -i, -j

If, as is likely, you don't recall what those are, just use the 
defaults - things can't get any worse. If /dev/hda3 was ext3, then do

mke2fs -n -j /dev/hda3

otherwise just do

mke2fs -n /dev/hda3


These do the actions of mke2fs without actually writing to disk, and so 
they will print a list of alternate superblocks which you can offer to 
e2fsck -b.

> I await the wisdom of the ILUG gurus with bated breath.

You can let the CO2 out now. But a word of warning - this is unlikely 
to help a whole lot. In maybe 8 years using Linux, and 18 using Unix, I 
have NEVER seen the use of an alternate superblock do any good.


Niall