[ILUG] Dead disc?

[Pádraig Brady]

On 06/10/10 20:40, Brendan Halpin wrote:
> On Wed, Oct 06 2010, Brendan Halpin wrote:
> 
>> Thanks everyone for the suggestions.
>>
>> Pádraig Brady wrote:
>>
>>> sounds like someone messed with your partition table
>>> (using a "recovery cd" of some sort?).
>>
>> That's what I'm thinking. 
>>
>>> You should then be able to use grub and fdisk
>>> to recreate mbr and partition tables etc.
>>> If you don't know offsets then you may need
>>> to search for your file systems with something
>>> like gpart.
>>
>> OK, that's where I am, and I've just got gpart to spit out a lot of
>> numbers to me which look like my missing partitions, with size and
>> offset in megabytes. How do I use this? Via fdisk? gparted?
> 
> Philip Trickett pointed me to "gpart -W ..." and now I can read several,
> but not all, of my partitions (home, /, /usr) which means I can see my
> fstab. That shows that I did use LVM the last time (I don't understand
> LVM!) and that I am missing /var /and /usr/local -- it would be good to
> have these back too. Looking at it in GParted doesn't help: 100%
> unallocated according to that!
> 
> fdisk gives this:
> 
> +---------------------------------------------------------------------
> |Disk /dev/sda: 160.0 GB, 160041885696 bytes
> |255 heads, 63 sectors/track, 19457 cylinders
> |Units = cylinders of 16065 * 512 = 8225280 bytes
> |Disk identifier: 0x38000000
> |
> |   Device Boot      Start         End      Blocks   Id  System
> |/dev/sda1               1        1305    10482376    7  HPFS/NTFS
> |/dev/sda2            1306        3736    19527000    7  HPFS/NTFS
> |/dev/sda3            3737        4399     5325547+   5  Extended
> |/dev/sda4            7586       19196    93265324   83  Linux
> |/dev/sda5   *        3750        3791      337333+  83  Linux
> |/dev/sda6            3792        4764     7815591   83  Linux
> |/dev/sda7   ?      186466      186580      917750+  ed  Unknown
> +---------------------------------------------------------------------
> 
> These start and ends look crazy to me. Shouldn't the end of sda3 overlap
> with the logical partitions it contains? I presume the start and end for
> sda7 are just nonsense?

I guess gpart is being unclever with the extended partition 3
That should encapsulate all your extended partitions.
So I'd recreate that with fdisk with the end at 19457.

lvm complicates matters. Google will give you more
info that I could detail here.

If you get stuck, you could always just mount the above partitions
using the live CD, and copy the data somewhere before reinstalling.
As a shortcut to not need to copy it back, you could reinstall
(after verifying file systems with fsck) and mount /home without
reformating.

cheers,
Pádraig.