[linux-lvm] vg disappeared after replacing disc in raid10

[Björn Nadrowski]

You are certainly right. 
However, I have no clue what to do. 
The pvcreate was a hint given on the lvm pages at redhat. It should only have overwritten the UUID in the metadata, nothing else. 
Recreation of the volume group seemed  a good idea as I only had one volume group on the pv and therefore I did not see how this could have destroyed anything.
The (human-readable) data at the beginning of the device /dev/md127 is still there and does display the same information. Please see my posting
on ubuntuforums for more details. 
Did you look that up? Do you have any idea what I can do?

I am anyways prepared to give up in the foreseeable future. This would be a major blow to me, this computer contained a lot of
old programs and information - but as it goes, I never looked up most of it.
There are some programs on which I was working at the moment, loss of those would be my major inconvenience at the moment. 
But as my data recovery attempts seem to go nowhere, I will have to stop trying some day.




On Mar 25, 2013, at 21:36 , Stuart D Gathman <stuart at bmsi.com> wrote:

> Long ago, Nostradamus foresaw that on 03/25/2013 04:25 PM, Björn
> Nadrowski would write:
>> 
>> I did recreate the physical volume and the volume group using pvcreate and vgcreate, please see the description of the problem 
>> on ubuntuforums for further details.
>> 
> That was not a good idea.  You've now written over the major clue to
> what happened.   Examining the beginning of the PV for the metadata -
> perhaps offset or scrambled because of some inadvertent change to the
> raid10 parameters - should have been your major priority!
> 
> Theory 2: the md driver on the knoppix CD is an earlier version that
> puts metadata at the end of the volume, instead of at the beginning. 
> This would change the offsets of your metadata and extents.  It would
> not see the newer md raid metadata, and create a new drive.  I'm not
> sure if this theory is consistent with your history.
> 
> I *strongly* advise not doing any more writing to this device until you
> know *exactly* what happened.
> 
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