[TriLUG] saving extended partition info

[Joseph Mack NA3T]

On Sun, 22 Apr 2007, Alan Porter wrote:

>
>> I save the first 512bytes of a disk (the mbr) with dd
>
> I would feel a lot more comfortable with something like
>
>   fdisk -l > fdisk.out
>
> Recovery is a little harder, because I'd have to type in some
> numbers.  But copying raw bytes from the hard disk is just
> not transparent enough for me.  I prefer a method where I can
> use "vi" to view and edit the information in human-readable
> format.

that's what I'm looking for too.

As for recovery: yesterday I dd'ed a windows disk image onto 
/dev/hda (my main disk) instead of /dev/sda (my usb backup 
disk). It took me about a minute to realise that the light 
wasn't going to come on on the usb backup disk, to figure 
what I'd done and kill the dd. fdisk showed I now had a 
partition table for a windows disk on my linux machine. The 
machine was still happily running and so I dd'ed my copy of 
the original mbr back onto the linux disk, to find that 
everything (including the extended partitions) was still 
available except /dev (all garbage) and I'd lost a few files 
in /root. /etc and all other directories in / were fine.
Presumably the files in /dev were closet to the start of the 
disk, followed by /root.

I let all my other jobs complete, shut the machine down and 
moved the disk to a new machine were I found only the / 
partition to have problems. I should have fsck'ed using one 
of the alternate superblocks, but I used the standard one 
and wound up with a hosed partition, which I restored from 
the previous night's backup.

I'm now trying to figure out how to recover disks if I 
deliberately `dd if=/dev/zero` to the start of the disk.

Joe
-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!