Installing Arch Linux With LVM

The question is not "are you using LVM" but "why aren't you using LVM"?  (I'm politely ignoring Btfs for this posting, I'll post on that another time)

I won't get into the benefits of using the Logical Volume Manager (LVM) - but its a stable disk management system that his been in the Linux world since 1998 - and I can not imagine installing a Linux system (from laptop to server) without it.

I can go on - give you some war stories - but instead let me give you the few commands you include when installing Arch Linux with LVM.

Following the Installation Guide (or maybe the Beginners Guide), when you get to partitioning you will want to load this module.

modprobe dm-mod

Next you will partition your disk(s).  I will show you a simplified setup using MBR with a separate /boot partition (call me old school).  Notice /dev/sda2 type is Linux LVM.  You could create a single large partition, or even multiple Linux LVM type-partitions on different disks.



Next you need to setup LVM inside the Linux LVM type-partition.  First initialize the physical volume, the /dev/sda2 partition you created above.

pvcreate /dev/sda2

Next you need a volume group, keeping it simple I'll just create the one - naming it system.

vgcreate system /dev/sda2

Now your logical volumes, where the fun happens (notice the system volume group label).

lvcreate -L 25G -n root system
lvcreate -L 16G -n swap system
lvcreate -l 100%FREE -n home system

Now you come to the formatting portion of the instructions.  Its essentially the same, just the syntax is a little different.

mkfs.ext4 /dev/sda1
mkfs.ext4 /dev/mapper/system-root
mkfs.ext4 /dev/mapper/system-home

And the same for your swap logical volume.

mkswap /dev/mapper/system-swap
swapon /dev/mapper/system-swap

Now mount those bad-boys.

mount /dev/mapper/system-root /mnt
mkdir /mnt/home /mnt/boot
mount /dev/sda1 /mnt/boot
mount /dev/mapper/system-home /mnt/home

When you create your /etc/fstab ensure everything is correct.



Now edit your /etc/mkinitcpio.conf to add the lvm2 HOOK between block and filesystems so it looks like this.

HOOKS="base udev autodetect modconf block lvm2 filesystems keyboard fsck"

In the same file add dm-mod to MODULES.

MODULES="dm-mod"

Any time you edit that file, remember to run the following.

mkinitcpio -p linux

I didn't include the /boot partition in LVM or I would have had to include lvm module in /etc/default/grub, like this.  Remember to do this before creating the /boot/grub/grub.cfg

GRUB_PRELOAD_MODULES="part_gpt part_msdos lvm"

That is pretty much it.  You may get warnings when generating your /boot/grub/grub.cfg, but as long as there is no errors all should be good.

Continue with the remainder of your instructions and remember the most important thing - have fun with your Arch system!

This is just showing you how to install Arch Linux using LVM - not even touching on why you should do this or, now that its installed and configured, what you can do with it.