[clug] Canberra Linux user group- assistance needed

Leo Kliger lkliger at bigpond.net.au
Sat Apr 29 05:58:14 GMT 2006

Hi Neill,

Sounds touch and go - I would dd the entire disk to another one before I
did anything else.

>root at ubuntu:~# fsck -b 8193 /dev/VolGroup00/LogVol00
>fsck 1.38 (30-Jun-2005)
>e2fsck 1.38 (30-Jun-2005)
>fsck.ext3: Bad magic number in super-block while trying to
>open /dev/VolGroup00/LogVol00

Block 8193 is just an example super-block on a 1k block file-system. Not
necessarily the backup block on the ex3 partition in question. 

You need to determine the block size of the file-system.
Have you tried "tune2fs -l /dev/VolGroup00/LogVol00" ?

If the partition has 4k blocks then the first few super-blocks would
be:- 32768, 98304, 163840, 229376, 294912, 819200, 884736

If the partition has 2k blocks then the first few super-blocks would
be:- 16384, 49152, 81920, 114688, 147456, 409600, 442368, 802816,
1327104, 2048000

If the partition has 1k blocks then the first few super-blocks would
be:- 8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409, 663553,
        1024001, 1990657, 2809857

You could then run:-
#e2fsck -b "correct backup super-block" /dev/VolGroup00/LogVol00"

I could lend you a 120GB drive in a usb enclosure if it helps - I live
out past Hall though. 



On Sat, 2006-04-29 at 14:23 +1000, Neill Cox wrote: 
> OK.
> Having been round to visit, and found a slightly more complicated problem
> than I was hoping for I'm begging for help from the list's collective
> wisdom.
> Basically the Kendircks have a PIV with Fedora Core 4 installed on a
> removeable IDE hard disk (one of the ones that uses a caddy to allow you
> to swap drives).
> Vanessa thinks that the machine may have been powered off without a proper
> shutdown, but can't be definite.
> FC4 appears to have been installed on 80GB drive.
> The drive is manged by LVM - one physical volume, two logical.  I have
> almost zero experience of lvm.
> The logical volumes appear to be an ext3 partition and a swap partition.
> The ext3 partition will not mount.
> When the PC is booted the kernel panics with the message:
> EXT3-fs dm-0 couldn't mount because of unsupported optional features
> (80008000)
> mount error 22 mounting ext 3
> I've attached to this email the results of poking at the drive with
> various commands in the hope that someone can make some helpful
> suggestions.
> It looks like the drive is physically fine but that the ext3 partition is
> hosed.  Hopefully this can be repaired.
> If no one has a better idea (and I hope someone does).  My next step is
> probably to go back with a copy of ubcd or similar to see if it can sort
> the mess out.
> I'm happy to be somebody's remote hands for this one, or I'm sure anyone
> else who wants to go and visit would be welcome.
> Thanks,
> Neill

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