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Re: [LUG] grub error 25

 

 On 02/12/11 17:52, Pat Sumner wrote:
> There was a discussion about grub error 17 a while back but this
> doesn't seem to be in the archive; a search on  'grub' just returned
> zero. Can anyone point me to the discussion?
>
> The PC (Debian lenny) has two SATA discs and I get no further than the
> grub error. I have put a Knoppix live DVD in and what I have learned is
>   1. I can mount /dev/sda, which has four partitions;
>   2. dmesg starts off with a lot of error messages about ata
>   3. I can't mount the other disc, /dev/sdb,  which is the one with
> all the important files on
>       it;
>    4. /dev/sdb has a reiserfs file system and dmesg  says
>
> [ 4870.294237] REISERFS warning (device sdb): sh-2006
> read_super_block: bread failed (dev sdb, block 2, size 4096)
> [ 4870.294259] REISERFS warning (device sdb): sh-2006
> read_super_block: bread failed (dev sdb, block 16, size 4096)
> [ 4870.294264] REISERFS warning (device sdb): sh-2021
> reiserfs_fill_super: can not find reiserfs
>
> What I am hoping you can tell me is (a) whether this disk and all its
> files are lost, or (b) is there a recovery program I can get that will
> extract at least  some of them. Is there maybe a live OS with more
> comprehensive resue capabilities than Knoppix 6.7?
>
> Hopefully,
>
> Tony
> [masquerading as Pat Sumner cos my own PC is not working...]
>
>

You have two problems here, deal with them separately. Physically
disconnect sdb initially to see if you can at least get past problem 1,
which is booting debian normally from sda. Post the full error you're
getting from grub, and tell us if you are using grub-legacy (v1) or
grub-pc (v2, which is now the default on lenny) as it makes a big
difference. I have no idea why people still seem to default to knoppix
as their "go to" live disk, it has no significant advantage over any
other random live CD and significant disadvantages over most - get a
copy of at least the supergrub and grml distros and keep them to hand
for exactly this kind of problem.

As usual, ignore anyone telling you to randomly do "stuff" to the
potentially damaged sdb - if you value your data and sanity at all, back
it up immediately with a block level copy using dd to an image. All
further analysis and fixes can then be attempted on the safe image
rather than wreaking further havoc on the physical version. Your data
should be at least in part recoverable, even if you have to use strings
and a hex editor: just don't do anything hasty.

As for reiserfs, why on earth is on that any system at all in 2011? You
may have a sound technical reason but I seriously, seriously doubt it.

I deal with this kind of problem a lot so hopefully with more
information can point you in the right direction.

Cheers,

Mat

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