A simple introduction to working with LVM

http://www.debian-administration.org/articles/410

A simple introduction to working with LVM

Posted by Steve on Wed 28 Jun 2006 at 21:22

Tags: cookbook, filesystems, howto, lvm

The logical volume manager allows you to create and manage the storage of your

servers in a very useful manner; adding, removing, and resizing partitions on demand.

Getting started with LVM can be a little confusing to newcomer so this guide intends

to show the basics in a simple manner.

There several pieces of terminology that you'll need to understand to make the best

use of LVM. The most important things you must know are:

• physical volumes

o These are your physical disks, or disk partitions, such

as /dev/hda or /dev/hdb1. These are what you'd be used to using when

mounting/unmounting things. Using LVM we can combine multiple

physical volumes into volume groups.

• volume groups

o A volume group is comprised of real physical volumes, and is the

storage used to create logical volumes which you can

create/resize/remove and use. You can consider a volume group as a

"virtual partition" which is comprised of an arbitary number

of physicalvolumes.

• logical volumes

o These are the volumes that you'll ultimately end up mounting upon your

system. They can be added, removed, and resized on the fly. Since these

are contained in the volume groups they can be bigger than any single

physical volume you might have. (ie. 4x5Gb drives can be combined

into one 20Gb volume group, and you can then create two 10Gb logical

volumes.)

Logically these are stacked from top to bottom like this: