[linux-lvm] LVM2 Recovery after Filesystem Code Change

meLon earthmelon at gmail.com
Mon May 20 17:09:00 UTC 2013


After noticing warnings saying "Incorrect metadata area header checksum"
when using pv/lv commands I looked into what could be causing the issue and
attempted to fix the issue.  I had a HDD with an ext2 /boot partition and
an LVM containing an encrypted volume.  I ran sfdisk to change the second
partition's filesystem code to 8e and rebooted.

After rebooting, I was shown an error when I would normally type in my
encrypted volume's passphrase.  I cannot remember the exact error, but I
was unable to recover.  I pulled the HDD and installed Linux onto another
HDD.

I put the old HDD containing data I would like to recover in another
machine and tried to see what I could do.  pvscan and lvscan would show a
pv, but would report the Incorrect metadata area header checksum warning.
 I tried to mount my /boot partition, but it said something along the lines
of "Unknown filesystem type LVM.....".  However, if I used *-t ext2*, the
/boot partition would mount without a problem.  I ran fsck.ext4 (big
mistake) on the /boot partition which destroyed all of the data on that
partition.  The destruction of /boot is not important to me, but the steps
I took to do it may give some insight on my LVM issue.

At this point, I believe that I accidentally told sfdisk that my /boot was
an LVM partition which was why I was unable to boot into my os.


Now I have the HDD  set up and when running pvdisplay I see the HDD, but it
does not show a VG name and reports it as a "new physical volume".  Because
it's not assigned to a VG, it does not get placed in /dev/mapper, which
means I cannot run cryptsetup to unlock the drive.

Any recovery/backup information that I see being used by other people to
rectify similar situations resided on the drive I am having problems with,
which makes it impossible for me to use such data for recovery.

I am hoping there is a way to assign this PV to a VG without destroying any
data on the disk so that I can decrypt it and export the data from the
drive.

I am currently dd'ing the drive to another drive so that any suggestions I
get from this mailing list can be executed without taking me further from
retrieving my data.

I appreciate you taking the time to read this email and thank you for any
input or suggestions you may have.


  "/dev/sda1" is a new physical volume of "1.36 TiB"
  --- NEW Physical volume ---
  PV Name               /dev/sda1
  VG Name
  PV Size               1.36 TiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               ajtoix-aTPi-XXXX-XXXX-XXXX-XXXX-XXXXXX




-- 
- meLon
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