[linux-lvm] Severe problem: data lost while adding a partition

[Sander Alberink]

Hello all,

Sorry to reply to myself, but I really am stuck on this one. Any 
pointers would be much appreciated...

I have gotten the vgcreate to work (this was caused by me now using 
devfs (so I need to supply DevFS filenames). I also executed an lvcreate 
-l 399 (which was the maximum number of PE's available) on the resulting 
volume group. However, I cannot mount the resulting logical volume.
It used to contain a reiserfs filesystem, a reiserfsck --check yields no 
errors, but I am unable to mount the filesystem.
I am getting rather lost now.....

Hope someone can help!

Best regards,

Sander

Sander Alberink wrote:

> Hi all,
>
> Thanks for the reply. At the moment I have re-initialized the PV's via 
> pvcreate -ff. However, trying to reconstruct a new volume group yields 
> me the following output:
>
> # vgcreate -v home /dev/hda[1,4,6,7]
> vgcreate -- checking volume group name
> vgcreate -- checking volume group directory existence
> vgcreate -- locking logical volume manager
> vgcreate -- checking volume group "home" existence
> vgcreate -- counting all existing volume groups
> vgcreate -- reading all physical volume data from disks
> vgcreate -- checking if all given physical volumes in command line are 
> new
> vgcreate -- checking physical volumes name "/dev/hda1"
> vgcreate -- checking physical volumes name "/dev/hda4"
> vgcreate -- checking physical volumes name "/dev/hda6"
> vgcreate -- checking physical volumes name "/dev/hda7"
> vgcreate -- no valid physical volumes in command line
> #
>
> So apparently something is not OK. But what can that be? Any pointers 
> would be appreciated!
>
>>> I really appreciate your help in this. However, I am rather 
>>> reluctant to
>>> dive in and be hasty in my commands. I really don't want to destroy my
>>> data.... As I understand it, pvcreate -ff would re-initialize the
>>> physical volume. As I understand it, I will have to add them to a 
>>> volume
>>> group again. But will the filesystem still be intact after that then?
>>>
>>> Sorry if this sound like a beginner question to you. It very well might
>>> be, but I'd rather be careful....
>>
>>
>>
>> Thing to understand is that LVM commands update a small
>> header on the phyiscal volume. You can munge the LVM
>> portion without touching your data at all. In this case
>> the data has no way of knowing that anything happend to
>> the LVM portion of life: they live in entirely different
>> parts of the disk drive. 
>