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I had used Ubuntu 12.04 to build a mdadm software raid 1 array from 2 harddisks, and then I created a LVM on this array and used this LVM to install my Ubuntu 12.04 system on it (I still have a boot partition outside the LVM).

Recently, my system could not boot any more (I guess the 5 years harddisks may be too old and have some problems). I now boot my system from an Ubuntu 16.04 live CD but I could not see the data in my LVM volume.

Could anyone guide me the procedures to view my data in the LVM volume? Thanks for any suggestion.

EDIT : In fact, the LVM is built on 2 mdadm software raid 1 arrays. The structure is listed below :

/dev/sda5 + /dev/sdb5 -> A1 (1st raid 1 array)
/dev/sda6 + /dev/sdb6 -> A2 (2nd raid 1 array)
A1 + A2 -> LV1 (LVM volume built on 2 raid 1 arrays)

When I boot my computer using Ubuntu 16.04 live CD, the output for the following commands is :

ubuntu@ubuntu:~$ sudo lvscan
ubuntu@ubuntu:~$ sudo vgscan
  Reading all physical volumes.  This may take a while...
ubuntu@ubuntu:~$ sudo pvscan
  No matching physical volumes found
ubuntu@ubuntu:~$ 

It seems that I could not find my LVM volume.

What could I do to fix this problem? Any comment?

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You need to install mdadm (raid deamon) which is not present by default on the live Cd. Then you can perform the "assemble scan operation"

sudo apt-get install mdadm -y 
sudo mdadm --assemble --scan

Then perform lvscan/vgscan

sudo vgscan
sudo lvscan

Then use sudo fdisk -l | grep dev to find your list of logical volumes

Then perform the fcsk with command like

sudo fsck -y /dev/mapper/NAME_OF_THE_LOGICAL_VOLUME

Regards,

Emmanuel

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  • Tested OK on my system. In addition, I use sudo vgchange -ay NAME_OF_THE_VOLUME_GROUP to activate my logical volume. – user1129812 Mar 26 '18 at 0:49

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