1. Introduction

Welcome, gentle reader.

This document is written to help enlighten you on what LVM is, how it works, and how you can use it to make your life easier. While there is an LVM FAQ, and even a German HOWTO, this document is written from a different perspective. It is a true 'HOWTO' in that it is very hands-on, while also imparting understanding (hopefully).

I should make it clear that I am not an author of the Linux Logical Volume Manager. I have great respect for the people who are, and hope to be able to cooperate with them.

It's even weirder, I don't even know the developers of LVM. I hope this will change soon. I apologise in advance for stepping on peoples toes.

1.1 Disclaimer & License

This document is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

If your disks melt and your company fires you - it's never our fault. Sorry. Make frequent backups and do your experiments on non-mission critical systems.

Furthermore, Richard Allen does not speak for his employer.

Linux is a registered trademark of Linus Torvalds.

1.2 Prior knowledge

Not much. If you have ever installed Linux and made a filesystem (fdisk/mkfs), you should be all set. As always when operating as root, caution is advised. Incorrect commands or any operation on device files may damage your existing data.

If you know how to configure HP/UX LVM you are almost done, Linux works almost exactly like the HP implementation.

1.3 Housekeeping notes

There are several things which should be noted about this document. While I wrote most of it, I really don't want it to stay that way. I am a strong believer in Open Source, so I encourage you to send feedback, updates, patches etcetera. Do not hesitate to inform us of typos or plain old errors.

If you feel to you are better qualified to maintain a section, or think that you can author and maintain new sections, you are welcome to do so. The SGML of this HOWTO is available via CVS. I envision this being a collaborative project.

In aid of this, you will find lots of FIXME notices. Patches are always welcome! Wherever you find a FIXME, you should know that you are treading unknown territory. This is not to say that there are no errors elsewhere, but be extra careful. If you have validated something, please let us know so I can remove the FIXME notice.

1.4 Access, CVS & submitting updates

The canonical location for the HOWTO is http://www.ds9a.nl/lvm-howto/.

We now have anonymous CVS access available for the world at large. This allows you to easily obtain the latest version of this HOWTO and to provide your changes and enhancements.

If you want to grab a copy of the HOWTO via CVS, here is how to do so:

$ export CVSROOT=:pserver:anon@outpost.ds9a.nl:/var/cvsroot
$ cvs login
CVS password: [enter 'cvs' (without 's)]
$ cvs co lvm-howto
cvs server: Updating lvm-howto
U lvm-howto/lvm-howto.sgml

If you spot an error, or want to add something, just fix it locally, and run "cvs diff -u", and send the result off to us.

A Makefile is supplied which should help you create postscript, dvi, pdf, html and plain text. You may need to install sgml-tools, ghostscript and tetex to get all formats.

1.5 Layout of this document

We will initially be explaining some basic stuff which is needed to do things. We do try however to include examples where this would aid comprehension.