Installing Arch Linux on ZFS

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The Zettabyte File System (ZFS) is an advanced copy-on-write filesystem designed to preserve data integrity from a multitude of possible corruption scenarios as well as provide simple administration features. ZFS makes disk administration effortless with support ZFS storage pools (zpools) and automatic mount handling. First released in 2005 for Solaris OS, ZFS has since become the flag bearer for next generation filesystems.

ZFS was first developed and released by Sun (now owned by Oracle) as Open Source Software licensed under the Wikipedia:Common Development and Distribution License (CDDL) which is famously incompatible with the GNU Public License. This incompatiblity prevents ZFS from being merged into the mainline kernel, and generally presents some obsticles for users that want to use ZFS in Linux. is a project funded by the Lawrence Livermore National Laboratory to develop a native Linux kernel module for its massive storage requirements and super computers.

Installing Arch Linux on a regular filesystem

1. Install Arch Linux to wherever you want with the default partition settings, select base-devel when selecting the packages to install, select syslinux as the bootloader, and boot into your new install.
2. Install some applications that we will be using:

# pacman -S git pbzip2

3. Install the splAUR and zfsAUR modules from the AUR.

Configuring the environment

1. Add the zfs hook to your HOOKS array in /etc/mkinitcpio.conf before filesystems and after sata, and make a new initramfs with mkinitcpio.

# vim /etc/mkinitcpio.conf
HOOKS="...sata zfs filesytems ..."
# mkinitcpio -p linux

2. Edit your fstab to only mount things not managed by ZFS (/boot, swap, cdrom?)

# vim /etc/fstab

3. Add zfs to your DAEMONS array in /etc/rc.conf:

# vim /etc/rc.conf
DAEMONS="syslog-ng zfs network ..."

and that's it for the setup portion.

Backing up Arch Linux

Make a temporary directory to bind / to only backup the / without any other mountpoints:

# mkdir /tmp/zfs
# mount -o bind / /tmp/zfs
# mount -o bind /boot /tmp/zfs/boot
# cd /tmp/zfs
# tar --exclude arch-zfs.tar --exclude var/cache/pacman/pkg -cvpf arch-zfs.tar .

Compress the tarball with pbzip2 (dont use bzip2.. it will take a much longer time since it's single-threaded, use pbzip2 if you have a multithreaded system)

# pbzip2 arch-zfs.tar

Save this file somewhere because we will be moving it to our new installation afterwards (arch-zfs.tar.bz2)

New install with ZFS as the filesystem

In order to partition the system, I was using System Rescue CD v2.5.1. The reason I'm using 2.5.1 is because it's the last version that had the native ZFS on Linux modules. Any version before or later does not have them. Since the link for 2.5.1 was removed from the author's website, I recommend you to use the Gentoo Live DVD 2012. , download the `livedvd-amd64-multilib-2012.1`. As of the release of Sabayon 9, the Sabayon liveDVD can be used for this purpose. While ZFS support exists on all editions, the most rich application suite exists in their KDE release, making it likely the most convenient for those who don't mind the added iso size.

Note: If anyone knows of another live cd that like sysresccd that has the ZFS on Linux modules, definitely feel free to add it here


Our system will be using GPT as the base and extlinux as the bootloader.

Let's create a directory to hold out zfs pool

# mkdir /mnt/pool

The layout will look like this:

/dev/sda1 8300 Linux FS 250M # This will be our /boot partition
/dev/sda2 8200 Linux Swap <YOUR_RAM * 1.5> # or w/e calculations you use
/dev/sda3 bf01 Rest of Disk # This will be the ZFS pool
Warning: You cannot put the swap inside the ZFS pool yet because it will have problems. This will probably be fixed in a future upstream version.
  1. Format the /boot partition as ext4 (or ext2-3)
# mkfs.ext4 /dev/sda1
  1. Make the swap and turn it on
# mkswap /dev/sda2
# swapon

Load up the spl/zfs modules (if needed)

# modprobe spl zfs

Create ZFS Pool and Mountpoints

# zpool create -o ashift=12 -o cachefile= -O normalization=formD -R /mnt/pool rpool /dev/sda3
# zfs create -o mountpoint=none rpool/ROOT
# zfs create -o mountpoint=/ rpool/ROOT/arch
# zfs create -o mountpoint=/home rpool/HOME
# zfs create -o mountpoint=/root rpool/HOME/root

Mount your /boot partition

# mkdir /mnt/pool/boot
# mount /dev/sda1 /mnt/pool/boot

Move the arch-zfs.tar.bz2 file to your system. You can use scp if it's over the network, or a flash drive if you are within walking distance.

# scp /arch-zfs.tar.bz2 root@<ip_of_new_computer>:/mnt/pool

Extract the Arch backup (Preloaded with ZFS modules and configured for ZFS)

# cd /mnt/pool
# tar -xjpvf arch-zfs.tar.bz2 .

Install Extlinux bootloader

Bind a few mountpoints in the chroot env before chroot so that extlinux can find the correct device

# mount --bind /proc ./proc
# mount --bind /dev ./dev
# mount --bind /sys ./sys
# env -i HOME=/root TERM=$TERM chroot . /bin/bash --login
# The below commands are executed within the chroot environment
# mkdir /boot/extlinux
# extlinux --install /boot/extlinux

Set correct boot flags in the GPT legacy bios and then flash gptmbr

# sgdisk /dev/sda --attributes=1:set:2
# sgdisk /dev/sda --atributes=1:show
# dd count=1 bs=440 conv=notrunc if=/usr/lib/syslinux/gptmbr.bin of=/dev/sda

Make an extlinux.conf

# cd /boot/extlinux
# vim extlinux.conf

Inside extlinux.conf put the following

UI menu.c32
    MENU LABEL Arch Linux
    LINUX /vmlinuz-linux
    INITRD /initramfs-linux.img
    APPEND zfs=rpool/ROOT/arch zfs_force=1

and save it.

That's it, restart your computer and you should be inside Arch on ZFS :)!