How-To: install Ubunutu 18.04 LTS on ZFS root

ubuntu-18.04-lts-on-zfs-root.md

How-To: install Ubunutu 18.04 LTS on ZFS root

DISCLAIMER: make sure you have backed up all your data before following these steps. Use these steps solely on your own risk!

Basic install

• Install Ubuntu 18.04 using server installer, but change partitioning as follows

EFI partition: 1gb
/boot partition ext4: 1gb
/ partition ext4: 4gb (or size for swap usage)

Prepare and partition for ZFS

• Update to latest

apt-get update && apt-get upgrade

• Add latest ZFS version

add-apt-repository --yes ppa:jonathonf/zfs

• Install zfs tools

apt install zfs-dkms zfs-initramfs gdisk

• Add partitions to partition table

gdisk /dev/sda

• Enter n for new partition
• Enter +512G as size and a504 as partition type
• Enter p to see partition table
• Enter w to write partition table
• Repeat for sdb
• Reboot
• Create pool

zpool create -o ashift=12 -O atime=off -O compression=lz4 tank mirror /dev/disk/by-id/XXXXXpartX  /dev/disk/by-id/YYYYYpartY

• Create datasets

zfs create -o mountpoint=none -o canmount=off tank/os
zfs create tank/os/root

• Copy / to ZFS

rsync -a --one-file-system / /tank/os/root/

Make system bootable

• Change into chroot environment

cd /tank/os/root
mount --bind /boot boot
mount --bind /dev dev
mount --bind /proc proc
mount --bind /sys sys
mount --bind /run run
chroot .

Update grub

update-grub
grub-install /dev/sda
grub-install /dev/sdb

Reboot and select ext4 install

exit
reboot

Set root mountpoint

zfs set mountpoint=legacy /tank/os/root/

Reboot into ZFS system

reboot

Verify ZFS is now root OS

zfs list

Diagnostic: check for ZFS in initrd

$ lsinitramfs /boot/initrd.img-4.8.0-58-generic | grep zfs