9/17/2017 - 9:43 PM

Arch Install on BTRFS Subvolumes

Setup guide for the partitioning, filesystem creation, subvolume creation, mounting, and then later bootstrapping Use as general guide along with the regular official wiki approach

Arch Linux btrfs install


  • Plenty of storage - snapshots will take lot of space
  • Latest Arch Linux install iso because those have newer kernels and more bugfixes in btrfs.
  • Have previous experience with installing Arch (like you can install arch with a blind fold).

1. Parititions

We will need two of them, one for /boot and the other one will be a btrfs partition with subvolumes.

  1. /dev/sda1 - this will be /boot with vfat filesystem because UEFI or syslinux for legacy BIOS boot
    mkfs.fat -F32 /dev/sda1
  2. /dev/sda2 - btrfs with bunch of subvolumes
    mkfs.btrfs /dev/sda2

I would recommend to use GPT partitioning scheme because it is just better, unless you want to do windows dualboot then I'm just sorry for you...

2. btrfs subvolumes

We will create few of them to support easy snapshoting with snapper

  1. Mount the root btrfs volume

    mount /dev/sda2 /mnt
  2. Create subvolume for root, home, var and one for snapshots

    btrfs subvolume create /mnt/@root
    btrfs subvolume create /mnt/@var
    btrfs subvolume create /mnt/@home
    btrfs subvolume create /mnt/@snapshots
  3. Mount them.

    umount /mnt
    mount -o noatime,compress=lzo,space_cache,subvol=@root /dev/sda2 /mnt
    mkdir /mnt/{boot,var,home,.snapshots}
    mount -o noatime,compress=lzo,space_cache,subvol=@var /dev/sda2 /mnt/var
    mount -o noatime,compress=lzo,space_cache,subvol=@home /dev/sda2 /mnt/home
    mount -o noatime,compress=lzo,space_cache,subvol=@snapshots /dev/sda2 /mnt/.snapshots

pacstrap and other normal shit you do when installing arch

Make sure that fstab is okay after you finish

Snapshot time

You can create snapshots like so

btrfs subvolume snapshot -r / /.snapshots/@root-`date +%F-%R`

And to restore from snapshot you just delete the currently used @root and replace it with a earlier snapshot

mount /dev/sda2 /mnt
btrfs subvolume delete /mnt/@root`
brtfs subvolume snapshot /mnt/@snapshots/@root-2015-08-10-20:19 /mnt/@root

and then just reboot :)

you will probably want to use Snapper or something like that to manage your snapshots.

Random notes

  1. syslinux sould be capable of booting a btrfs volume but afaik it is just talk, I havent found anyone in the internet who has a working syslinux btrfs boot without seperate /boot parition. Only GRUB is capable of booting from bare btrfs file system.
  2. /boot is not snapshottable with this setup, someone somewhere sugested to create a systemd service to copy files from btrfs /boot to your seperate FAT32 ESP partition when files change in /boot folder. I havent tried that yet.