Installing Arch Linux on ZFS
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This article details the steps required to install Arch Linux onto a root ZFS filesystem. This article supplements the Beginners' Guide.
Contents
Installing archzfs
Using the archzfs repository is highly recommended for effortless updates.
Embedding archzfs into archiso
See ZFS#Embed_the_archzfs_packages_into_an_archiso.
Using the archzfs repository
Activate the required network connection and then edit /etc/pacman.d/mirrorlist
and configure the mirrors for pacman to use. Once that is done, edit /etc/pacman.conf
and add the archzfs repository:
# nano /etc/pacman.conf
[demz-repo-core] Server = http://demizerone.com/$repo/$arch
Next, add the archzfs maintainer's PGP key to the local trust:
# pacman-key -r 0EE7A126 # pacman-key --lsign-key 0EE7A126
Finally, update the pacman databases and install archzfs:
# pacman -Syy
This is also the best time to install your favorite text editor, otherwise nano will have to be used.
# pacman -S archzfs dosfstools gptfdisk vim
Partition the destination drive
Review Beginners'_Guide#Prepare_the_storage_drive for information on determining the partition table type to use for ZFS. ZFS supports GPT and MBR partition tables.
ZFS manages its own partitions, so only a basic partition table scheme is required. The partition that will contain the ZFS filesystem should be of the type bf00
, or "Solaris Root".
Partition scheme
Here is an example of a basic partition scheme that could be employed for your ZFS root setup:
Part Size Type ---- ---- ------------------------- 1 512M Ext boot partition (8300) 2 XXXG Solaris Root (bf00)
An additional partition may be required depending on your hardware and chosen bootloader. Consult Beginners'_Guide#Install_and_configure_a_bootloader for more info.
Format the destination disk
Format the boot partition as well as any other system partitions. Do not do anything to the Solaris partition, ZFS will manage it.
Setup the ZFS filesystem
First, make sure the ZFS modules are loaded,
# modprobe zfs
Create the root zpool
# zpool create zroot /dev/disk/by-id/<id-to-partition>
Create necessary filesystems
If so desired, sub-filesystem mount points such as /home and /root can be created with the following commands:
# zfs create zroot/home # zfs create zroot/root
Note that if you want to use other datasets for system directories ( /var or /etc included ) your system will not boot unless they are listed in /etc/fstab! We will address that at the appropriate time in this tutorial.
Swap partition
ZFS does not allow the use swapfiles, but it is possible to use a ZFS volume as swap partition. It is important to set the ZVOL block size to match the system page size; for x86_64 systems that is 4k.
Create a 8gb (or whatever is required) ZFS volume:
# zfs create -V 8G -b 4K <pool>/swap
Initialize and enable the volume as a swap partition:
# mkswap /dev/zvol/<pool>/swap # swapon /dev/zvol/<pool>/swap
After using pacstrap
to install the base system, edit /<root>/etc/fstab
to ensure the swap partition is mounted at boot:
/dev/zvol/<pool>/swap none swap defaults 0 0
Make sure to unmount all ZFS filesystems before rebooting the machine, otherwise any ZFS pools will refuse to be imported:
# zfs umount -a
Configure the root filesystem
First, set the mount point of the root filesystem:
# zfs set mountpoint=/ zroot
and optionally, any sub-filesystems:
# zfs set mountpoint=/home zroot/home # zfs set mountpoint=/root zroot/root
Set the bootfs property on the descendant root filesystem so the boot loader knows where to find the operating system.
# zpool set bootfs=zroot zroot
Export the pool,
# zpool export zroot
Finally, re-import the pool,
# zpool import -d /dev/disk/by-id -R /mnt zroot
If there is an error in this step, you can export the pool to redo the command. The ZFS filesystem is now ready to use.
Install and configure Arch Linux
Follow the following steps using the Beginners' Guide. It will be noted where special consideration must be taken for ZFSonLinux.
- First mount any boot or system partitions using the mount command.
- Install the base system.
- The procedure described in Beginners' Guide#Generate an fstab is usually overkill for ZFS. ZFS usually auto mounts its own partitions, so we do not need ZFS partitions in fstab file, unless the user made datasets of system directories. To generate the fstab for filesystems, use:
# genfstab -U -p /mnt | grep boot >> /mnt/etc/fstab
- Edit the /etc/fstab:
- When creating the initial ramdisk, first edit
/etc/mkinitcpio.conf
and addzfs
before filesystems. Also, movekeyboard
hook beforezfs
so you can type in console if something goes wrong. You may also remove fsck (if you are not using Ext3 or Ext4). Your HOOKS line should look something like this:HOOKS="base udev autodetect modconf block keyboard zfs filesystems"
- Regenerate the initramfs with the command:
# mkinitcpio -p linux
Install and configure the bootloader
For BIOS motherboards
Follow Grub2#BIOS_systems_2 to install grub onto your disk. grub-mkconfig
does not properly detect the ZFS filesystem, so it is necessary to edit grub.cfg
manually:
/boot/grub/grub.cfg
set timeout=2 set default=0 # (0) Arch Linux menuentry "Arch Linux" { set root=(hd0,1) linux /vmlinuz-linux zfs=zroot initrd /initramfs-linux.img }
For UEFI motherboards
Use EFISTUB
and rEFInd
for the UEFI boot loader. See Beginners' Guide#For UEFI motherboards. The kernel parameters in refind_linux.conf
for ZFS should include zfs=bootfs
or zfs=zroot
so the system can boot from ZFS. The 'root' and 'rootfstype' parameters aren't needed.
Unmount and restart
This is it, we are done!
# exit # umount /mnt/boot # zfs umount -a # zpool export zroot # reboot