Mounting a LVM partition from LiveCD

Imagine that your "/" partition is an  LVM and it is corrupted. You need to  perform an fsck inorder to boot the system.

Now, get a live CD and boot your system to live cd.

1) Check if lvm2 packages are installed. Else, you can install it via yum.

2) Run the command "fdisk -l" to see if the harddisk partitions are detected. 

3) Run pvscan to scan all disks for physical volume. This to make sure that the LVM harddisk is        detected by  Centos.

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# pvscan

PV /dev/sda2 VG VolGroup00 lvm2 [74.41 GB / 32.00 MB free]

Total: 1 [74.41 GB] / in use: 1 [74.41 GB] / in no VG: 0 [0 ]

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4) After that run vgscan to scan disks for volume groups.

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# vgscan

Reading all physical volumes. This may take a while...

Found volume group "VolGroup00" using metadata type lvm2

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5) Activate all volume groups available.

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# vgchange -a y

2 logical volume(s) in volume group "VolGroup00" now active

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6)  Run lvscan to scan all disks for logical volume. You can see partitions inside the hard disk now active.

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# lvscan

ACTIVE '/dev/VolGroup00/LogVol00' [72.44 GB] inherit

ACTIVE '/dev/VolGroup00/LogVol01' [1.94 GB] inherit

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7) Mount the partition to any directory you want, usually to /mnt

# mount /dev/VolGroup00/LogVol00 /mnt

8) You can access the partition in the /mnt directory and can backup your data