Linux Logical Volume Manager (LVM) Introduction

The Linux Logical Volume Manager (LVM) enables you to set up one filesystem on multiple partitions. IF you are running out of space in one partition and if you want to add more space to that partition, you can use Logical Volume Manager (LVM).

Logical Volume Manager (LVM) can be considered as a thin software layer on top of multiple hard disks and partitions, which creates an illusion of continuity and ease-of-use for managing hard-drive replacement, repartitioning, and backups.

Following are the important advantages of implementing Logical Volume Manager (LVM).

• Managing large hard disk farms by letting you add disks, replace disks, and other disk management functions without disrupting the services running.

• On workstations Logical Volume Manager (LVM) allows you to resize your disk partitions easily as needed.

• Making backups by taking "snapshots."

• Creating single logical volumes of multiple physical volumes or hard disks.

Three important terms which are related with Logical Volume Manager (LVM) are Physical Volume, Volume Group and Logical Volume.

The concept is like you have one or more physical volumes (dev/sde1, /dev/sde2, /dev/sdf1, /dev/sdf2, /dev/sdg as in our example), and on these physical volumes you create one or more volume groups, and in each volume group you can create one or more logical volumes.