Logical Volume Management (LVM) is a method of space allocating on mass-storage devices.

It can provide superior features to the traditional partitioning schema such as concatenating, striping or combining partitions, re-sizing or moving partitions, potentially without rebooting.

Some related commands that will help with the LVM commands are:

lsblk
blkid /dev/mapper/lg_name-lv_name

Displaying information:

pvdisplay
vgdisplay
lvdisplay
lvs

Claiming a new Physical device to extend an existent Logical Volume:

pvcreate /dev/sdb
vgextend vg_name /dev/sdb
lvextend -L +5G /dev/mapper/lg_name-lv_name
resize2fs /dev/mapper/lg_name-lv_name

Extending an existing Logical Volume to the whole extension of the Logical Group:

lvextend --resizefs -l +100%FREE /dev/mapper/lg_name-lv_name

Creating new Logical Volumes on the same new Volume Group:

vgcreate vg2_name /dev/sdc
lvcreate vg2_name -L 10G -n lv2_name
mkfs.ext4 /dev/mapper/vg2_name-lv2_name
lvcreate vg2_name -L 10G -n lv3_name
mkfs.ext4 /dev/mapper/vg2_name-lv3_name
lvcreate /dev/mapper/vg2_name-lv3_name -L 5G -s -n lv3_snapshot
mount /dev/mapper/vg2_name-lv3_snapshot /mount_point/
lvconvert --merge /dev/mapper/vg2_name-lv3_snapshot
lvchange -an /dev/mapper/vg2_name-lv3_name
lvchange -ay /dev/mapper/vg2_name-lv3_name