[CentOS] OT: Fortunate clueless dd chum - lvm recovery

[Ross Walker]

On Aug 14, 2009, at 12:48 PM, Robert Nichols  
<rnicholsNOSPAM at comcast.net> wrote:

> Ross Walker wrote:
>> On Fri, Aug 14, 2009 at 5:00 AM, Chan Chung Hang
>> Christopher<christopher.chan at bradbury.edu.hk> wrote:
>>
>> Question now is, was the first sector of partition 1 damaged (was it
>> 63 or 64 sectors dd'd)?
>>
>> If so it will require a more tricky procedure to fix.
>
> No, the ext2 file system does not use the first 1K block of the  
> partition.
> That space is left free for a boot loader.  The first super block of  
> the
> file system is the 2nd 1K block of the partition, and even if that  
> gets
> overwritten it is easily recovered from one of the backup super  
> blocks.

I did not know that, good information.

So stage2 is written in first 1k of the partition?

Ah but I believe the OP has the partition setup as a LVM PV. Question  
is does LVM leave the first 1k free for a stage2 boot loader?

And if the LVM metadata is corrupt is there a second copy at the end  
of the PV?

-Ross