Submitted by “This guide shows how to work with LVM on Linux. It also describes how to use LVM together with RAID1 in an extra chapter. As LVM is a rather abstract topic, this article comes with a Debian Etch VMware image that you can download and start, and on that Debian Etch system you can run all the commands I execute here and compare your results with mine. Through this practical approach you should get used to LVM very fast.”
Great beginners guide. I’d love to have that some months ago when I was starting out with LVM
.
Anyway, Enterprise Volume Management System (EVMS) http://evms.sourceforge.net/ includes an LVM2 plug-in as well as RAID and tons of other features and technologies able to be managed under one single tool (CLI, NCurses and GUI options).
If you are about to start using LVM (and RAID), take a look at what EVMS can offer, as you may wish to switch later on.
Gentoo EVMS Howto: http://gentoo-wiki.com/HOWTO_setup_evms
Debian EVMS: http://wiki.debian.org/EVMS
Last Friday I recorded a live podcast on my experience with EVMS on Gentoo on the IT Students International talkcast. http://www.talkshoe.com/talkshoe/web/talkCast.jsp?masterId=5681
EVMS Episode MP3 file: http://recordings.talkshoe.com/TS-6507.mp3
Edited 2007-01-16 16:12
This seems to be a nice tutorial. Every system admin should at least learn what LVM can do, even if he chooses not to use it.
Ability to shrink/enlarge live file systems, and migrate data from old drive on the fly can save a lot of time. And snapshots makes tape backups much more robust.
However I cannot agree with EVMS suggestion. While having a GUI is nice and such, the cost of another layer only for this is not justifiable (from what I saw on their page, all the things EVMS provide can be easily done with LVM/MD tools (and some parted maybe)).
> However I cannot agree with EVMS suggestion. While
> having a GUI is nice and such, the cost of another
> layer only for this is not justifiable (from what I
> saw on their page, all the things EVMS provide can be
> easily done with LVM/MD tools (and some parted
> maybe)).
Hi sukru,
Interesting, I’d like to learn more about your view on the added layer issue. For instance, what do you consider to be the added cost?
From my perspective, though LVM is easy, EVMS volume manageablity is faster and *easier* than using the LVM tools. As volume management is not something I do on a regular basis, I kept forgetting the precise LVM commands, requiring a quick peak at a howto and the man pages to get familiar again. If I used LVM commands every day, I’d probably consider them due to some added flexibility(?).
Its kind of like driving cars with manual gearboxes, you have more flexibility and spend less gas, but you need to keep driving them regularly to keep the habit.
I still don’t have experience with MD(RAID) and would like to get some manageability feedback on using it with EVMS or in conjunction with LVM2.
Thank you.
I’m not against GUIs in general. I could use a good LVM2 GUI (the one that comes with redhat based systems is not good enough). However, EVMS seems to require another indirection in order to use the GUI.
We normally have: disk(partition) -> DM(LVM volume) -> file system
The EVMS makes it like this: disk(partition) -> LVM(volume) -> DM(LVM volume) -> DM(EVMS layer) -> file system
This is what I understood from the figures on their site. So it may be incorrect.
If it’s correct, then we’ll have another ~%0.5 overhead for the GUI. Additionally we may not know they support all the LVM2 features (current and any future ones) correctly in the upper layer.
For my priorities those are not justifiable. For other people they may be. There is not one single solution in this area.
(PS: I only had one EVMS experience, it was not good. After that I’ve always used LVM2 on my systems, and there has been no big problems).
Edited 2007-01-17 04:04
Thank you sukru for your insight.
Setting up the EVMS volumes indeed takes more steps, and the lack of updated LVM2 features can be an issue to some people.
I though it said LLVM, and i rejoiced for some more info on its usage.
Maybe i need new glasses?