Installing Arch Linux on ZFS
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.
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 AUR.AUR and AUR modules from the
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 .
# 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. http://torrents.gentoo.org/ , 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.
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
- Format the /boot partition as ext4 (or ext2-3)
# mkfs.ext4 /dev/sda1
- 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
PROMPT 0 TIMEOUT 50 UI menu.c32
MENU TITLE Boot Menu DEFAULT arch
LABEL Arch 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 :)!