LVM

Introduction
LVM is the Logical Volume Manager for Linux. It's the new method to manage the disk storage in a way which is more flexible than the traditional disk partitioning. It allows you to create and modify volumes easily. The standard partitioning method has many limitations: when you shrink a partition which is at the end of your disk, you have to move the partitions if you want to reallocate this space to grow another partition. With LVM you don't have such problems.

Storage Level Types
Here are the three levels of storage:


 * Physical Volume (PV): This is the physical storage used by LVM. it may be an entire disk or an existing partition
 * Volume Group (VG): This is an aggregate of one or more Physical Volumes, and it contains Logical-Volumes.
 * Logical Volume (LV): This is the space offered by LVM that you can use as a partition to make a filesystem and store your files.

Diagram Of Arrangement
Looking from the top down:

your files - formatted file system - logical volume  (lv) - volume group    (vg) - physical volume (pv) -