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====== Ubuntu - LVM - Mount LVM partition from USB ======

Execute:

<code bash>
vgscan
vgchange -a y
</code>

as root and all the partitions should have devices created in the form /dev/volumegroup/logicalvolume, which you can then mount in the usual way:

<code bash>
mount /dev/volumegroup/logicalvolume /mnt/somewhere
</code>

----

===== Extended Method =====

1. Boot from a live disk or USB.


2. Search for these tools: **lvm2**.  If not found then install it.

<code bash>
sudo apt install lvm2
</code>


<WRAP info>
**NOTE:**  Some command below may return with the following error after installing LVM2:

<code bash>
/proc/misc: No entry for device-mapper found
Is device-mapper driver missing from kernel?
</code>


If so, then you load the **dm-mod** driver manually:

<code bash>
modprobe dm-mod
</code>

</WRAP>



3. Make sure the harddisk is recognised.

<code bash>
fdisk -lu
</code>


4. Run **pvscan** to scan all disks for physical volume.  This is to make sure your LVM harddisk is detected by Ubuntu.

<code bash>
pvscan
</code>

returns

<code>
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 ]
</code>


5. Run **vgscan** to scan disks for volume groups.

<code bash>
vgscan
</code>

returns

<code>
Reading all physical volumes. This may take a while...
Found volume group "VolGroup00" using metadata type lvm2
</code>


6. Activate all volume groups available.

<code bash>
vgchange -a y
</code>

returns

<code>
2 logical volume(s) in volume group "VolGroup00" now active
</code>


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

<code bash>
lvscan
</code>

returns

<code>
ACTIVE '/dev/VolGroup00/LogVol00' [72.44 GB] inherit
ACTIVE '/dev/VolGroup00/LogVol01' [1.94 GB] inherit
</code>


8. Mount the partition to any directory you want, usually to /mnt

<code bash>
mount /dev/VolGroup00/LogVol00 /mnt
</code>


9. Access the partition in the /mnt directory as required.

Script

<code bash>
DISK=mydisk

lvdisplay | grep $DISK | grep "LV Path" | sed 's/.* //g'
LV_DISK=$(lvdisplay | grep $DISK | grep "LV Path" | sed 's/.* //g')

fdisk -l $LV_DISK
fdisk -lu $LV_DISK | sed -n '/lv[0-9]p[1-3]/ p' | grep p1 | awk '{print $2}'

OFFSET=$(fdisk -lu $LV_DISK | sed -n '/lv[0-9]p[1-3]/ p' | grep p1 | awk '{print $2}')
OFFSET=$((OFFSET * 512))

MOUNT=/mnt/$DISK
mkdir -p $MOUNT
mount -o loop,offset=$OFFSET $LV_DISK $MOUNT
</code>