RAID and LVM

Xi0N · 2012-03-25 22:38:57

I'm currently setting up some computer with a raid5 configuration, but I see almost all the articles trend to set this up along with LVM.... why? I mean.... if I just want to use raid5 for creating one single partition for keeping my data, I don't need LVM, do I?
What the reason for using LVM along with RAID5 ?
Can anyone shed some light into this?
Thanks.

anrxc · 2012-03-26 00:37:01

I don't need LVM, do I?

No there is no need for LVM. Here's a list of reasons why one would want a volume manager
http://docs.redhat.com/docs/en-US/Red_H … al_volumes

KairiTech · 2012-03-27 17:39:43

Well I do if for two main reasons:

1. I want to use system encryption and if I didn't encrypt the RAID array first and then chop it into two LVM logical volumes (one for root and one for my data) I'll have to enter two passphrases.
2. I want to keep my data completely separate from root so when I reinstall (I'm an install junkie. What can I say?) my data will remain untouched because I'll only have to reformat the logical volume use for root.

Last edited by KairiTech (2012-03-27 18:16:19)

Ashren · 2012-03-27 20:33:47

LVM makes storage management very flexible. I always use LVM.

Xi0N · 2012-04-03 05:41:18

So, if all I want to is just setting up a raid5 volume with no encryption... it's kind of useless isn't it? I ask because I don't want to make the setup more complicated than what it already is.... you know... KISS....

Gcool · 2012-04-03 05:45:44

If you're only going to be creating one partition on your RAID5 array which you won't be resizing (often), then there's indeed not all that much use in using LVM.

Xi0N · 2012-04-03 05:55:50

But resizing is going to be the same, won't it?
I mean, if you want to resize a LVM partition, you resize it and then you also have to resize the underlying ext4 (i.e.) filesystem: In the future, if i add a new HD to the raid5 setup, i will have to resize anyway....
Thanks for making this clear

Ashren · 2012-04-03 08:59:53

Xi0N wrote:

But resizing is going to be the same, won't it?
I mean, if you want to resize a LVM partition, you resize it and then you also have to resize the underlying ext4 (i.e.) filesystem: In the future, if i add a new HD to the raid5 setup, i will have to resize anyway....
Thanks for making this clear

Yes, you need to resize your ext3/4 filesystem as well. You can do this with resize2fs on a mounted system - this only works when extending filesystems. The current resize2fs implementation only allows shrinking on unmounted systems.

The benefits of LVM2 clearly overrules the added "complexity" in my experience. I would never install Linux system without using LVM2 be it a enterprise or hobby system.

cedricmc · 2012-04-03 12:08:03

For ArchLinux installation on RAID5, read my thread.

Arch Linux

#1 2012-03-25 22:38:57

RAID and LVM

#2 2012-03-26 00:37:01

Re: RAID and LVM

#3 2012-03-27 17:39:43

Re: RAID and LVM

#4 2012-03-27 20:33:47

Re: RAID and LVM

#5 2012-04-03 05:41:18

Re: RAID and LVM

#6 2012-04-03 05:45:44

Re: RAID and LVM

#7 2012-04-03 05:55:50

Re: RAID and LVM

#8 2012-04-03 08:59:53

Re: RAID and LVM

#9 2012-04-03 12:08:03

Re: RAID and LVM

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