Installing UEFI ZFS Root on Ubuntu 19.04

As rumors of Ubuntu 19.04 including ZFS installer proved to be a bit premature, I guess it’s time for a slight adjustment to my previous ZFS instructions.

Again, all this is just a derivation on ZFS-on-Linux project’s instruction for older version.

As before, we first need to get into root prompt:

sudo -i

Followed by getting a few basic packages ready:

apt-add-repository universe
apt update
apt install --yes debootstrap gdisk zfs-initramfs

Disk setup is quite simple with only two partitions:

sgdisk --zap-all /dev/disk/by-id/ata_disk

sgdisk -n3:1M:+383M -t3:8300 -c3:Boot /dev/disk/by-id/ata_disk
sgdisk -n2:0:+128M -t2:EF00 -c2:EFI /dev/disk/by-id/ata_disk
sgdisk -n1:0:0 -t1:8300 -c1:Data /dev/disk/by-id/ata_disk

sgdisk --print /dev/disk/by-id/ata_disk

I believe full disk encryption should be a no-brainer so of course we set up LUKS:

cryptsetup luksFormat -q --cipher aes-xts-plain64 --key-size 512 \
--pbkdf pbkdf2 --hash sha256 /dev/disk/by-id/ata_disk-part1
cryptsetup luksOpen /dev/disk/by-id/ata_disk-part1 system

Creating ZFS stays the same as before:

zpool create -o ashift=12 -O atime=off -O canmount=off -O compression=lz4 \
-O normalization=formD -O xattr=sa -O mountpoint=none system /dev/mapper/system
zfs create -o canmount=noauto -o mountpoint=/mnt/system/ system/root
zfs mount system/root

Getting basic installation on our disks follows next:

debootstrap disco /mnt/system/
zfs set devices=off system
zfs list

And then we setup EFI boot partition:

yes | mkfs.ext4 /dev/disk/by-id/ata_disk-part3
mount /dev/disk/by-id/ata_disk-part3 /mnt/system/boot/

mkdir /mnt/system/boot/efi
mkfs.msdos -F 32 -n EFI /dev/disk/by-id/ata_disk-part2
mount /dev/disk/by-id/ata_disk-part2 /mnt/system/boot/efi

We need to ensure boot partition auto-mounts:

echo PARTUUID=$(blkid -s PARTUUID -o value /dev/disk/by-id/ata_disk-part3) \
/boot ext4 noatime,nofail,x-systemd.device-timeout=5s 0 1 >> /mnt/system/etc/fstab
echo PARTUUID=$(blkid -s PARTUUID -o value /dev/disk/by-id/ata_disk-part2) \
/boot/efi vfat noatime,nofail,x-systemd.device-timeout=5s 0 1 >> /mnt/system/etc/fstab
cat /mnt/system/etc/fstab

Before we start using anything, we should prepare a few necessary files:

echo "hostname" > /mnt/system/etc/hostname
sed 's/ubuntu/hostname/' /etc/hosts > /mnt/system/etc/hosts
sed '/cdrom/d' /etc/apt/sources.list > /mnt/system/etc/apt/sources.list
cp /etc/netplan/*.yaml /mnt/system/etc/netplan/

If you are installing via WiFi, you might as well copy your credentials:

mkdir -p /mnt/system/etc/NetworkManager/system-connections/
cp /etc/NetworkManager/system-connections/* /mnt/system/etc/NetworkManager/system-connections/

With chroot we can get the first taste of our new system:

mount --rbind --make-rslave /dev /mnt/system/dev
mount --rbind --make-rslave /proc /mnt/system/proc
mount --rbind --make-rslave /sys /mnt/system/sys
chroot /mnt/system/ /bin/bash --login

Now we can update our software:

apt update

Immediately followed with locale and time zone setup:

locale-gen --purge "en_US.UTF-8"
update-locale LANG=en_US.UTF-8 LANGUAGE=en_US
dpkg-reconfigure --frontend noninteractive locales

dpkg-reconfigure tzdata

Now we install Linux image and basic ZFS boot packages:

apt install --yes --no-install-recommends linux-image-generic
apt install --yes zfs-initramfs

Since we’re dealing with encrypted data, our cryptsetup should be also auto mounted:

apt install --yes cryptsetup keyutils

echo "system UUID=$(blkid -s UUID -o value /dev/disk/by-id/ata_disk-part1) \
none luks,discard,initramfs,keyscript=decrypt_keyctl" >> /etc/crypttab
cat /etc/crypttab

Now we get grub started:

apt install --yes grub-efi-amd64

And update our boot environment again (seeing errors is nothing unusual):

update-initramfs -u -k all

And then we finalize our grup setup:

grub-install --target=x86_64-efi --efi-directory=/boot/efi \
--bootloader-id=Ubuntu --recheck --no-floppy

Finally we get the rest of desktop system:

apt-get install --yes ubuntu-desktop samba linux-headers-generic
apt dist-upgrade --yes

We can omit creation of the swap dataset but I always find it handy:

zfs create -V 4G -b $(getconf PAGESIZE) -o compression=off -o logbias=throughput \
-o sync=always -o primarycache=metadata -o secondarycache=none system/swap
mkswap -f /dev/zvol/system/swap
echo "/dev/zvol/system/swap none swap defaults 0 0" >> /etc/fstab
echo RESUME=none > /etc/initramfs-tools/conf.d/resume

If one is so inclined, /home directory can get a separate dataset too:

rmdir /home
zfs create -o mountpoint=/home system/home

Only remaining thing before restart is to create user:

adduser user
usermod -a -G adm,cdrom,dip,lpadmin,plugdev,sambashare,sudo user
chown -R user:user /home/user

As install is ready, we can exit our chroot environment and reboot unmount our new environment. If unmount fails, just repeat it until it doesn’t. :)

umount -R /mnt/system

Finally we can correct root’s mount point and reboot:

zfs set mountpoint=/ system/root

Assuming nothing went wrong, your UEFI system is now ready.

[2019-10-27: Added –make-rslave]

PS: There are versions of this guide for other Ubuntu versions: 20.04 (native), 20.04 (luks), 19.10, and 18.10.

16 thoughts to “Installing UEFI ZFS Root on Ubuntu 19.04”

  1. What about doing a:
    # zpool export system
    # zpool import -N system
    # zfs set mountpoint=/ system/root
    before the reboot?

        1. it’s busy because you need to umount /mnt/system/boot, proc, dev,sys etc.

          if anything of these fails to umount, try umount -l

  2. After mounting dev, proc and sys they should be made rslaves:

    mount –make-rslave /mnt/system/proc
    mount –make-rslave /mnt/system/dev
    mount –make-rslave /mnt/system/sys

    This makes unmounting them less of a fresh hell. Also I’m not sure if there’s a reason for this, but you have the partition numbers backwards. Shouldn’t the ESP partition be 1 and the ZFS partition be 2?

    1. ESP partition has to be physically at the beginning of disk. However, it can be any number between 1 to 128. It’s matter of personal preference which number you give it. I like to give number 1 to my biggest partition and work from there. However, all this would work with EFI as the first partition too, i.e.:

      sgdisk -n1:1M:+511M -t1:EF00 /dev/disk/by-id/ata_disk
      sgdisk -n2:0:0      -t2:8300 /dev/disk/by-id/ata_disk

      As long as -part1 and -part2 suffixes are swapped too, there is no difference.

  3. This was awesome, thanks! I did this before with 16.04 and 18.04, and probably could have used the 18.04 directions for 19.04, but it was nie to have 19.04 specific directions.

    Worked like a charm!


  4. Awesome for you to post this How-To for 19.04! This is my first attempt at ZFS on Root. I’ve followed the and tried but without success. In my case I have a Dell T3500 with legacy bios (non UEFI). It’s ripe for use as a VM server for Docker, etc. Everything works well up till I install grub, it fails to install using the “BIOS” option given in the tuts. Would you have any suggestions or adjustment to your install how-to?


    1. Which version of Ubuntu you’re installing. If it’s 19.10, that could be the reason why it’s not working as ISO doesn’t contain all files needed to correctly set it up. I found that installing 19.04 and then upgrading to 19.10 works without issue. I also have a bit older BIOS boot guide at Take partition setup from it and follow newer guides when it comes to everything else.

      1. Thank you for your response!

        I’m installing on 19.04. Since this will be a VM server for Docker services I will avoid a short term release. Prior to seeing your response, I’ve successfully gotten a bootable system. What I found is that I needed to add “GRUB_DISABLE_OS_PROBER=true” to the /dev/default/grub file. The “apt install -y grub-pc” was, of course, using the default /etc/default/grub file. After the change I then reissued the the following commands where I was asked if I wanted to keep the original file. I am looking at testing “apt install -y grub-pc -o Dpkg::Options::=–force-confdef” to see if I can automate the selection for a scripted installation:

        apt reinstall -y grub-pc
        update-initramfs -u -k all
        grub-install $DISK1 (where $DISK1 = /dev/disks/by-id/)

        I’m now looking into why I am seeing the error “lz4 compression not supported” on boot. The system does boot and I am able to finalize the installation procedure. But errors are not something to ignore.

  5. Trying installing Ubuntu 19.10 with LUKS+ZFS but it fails at the `update-grub` step with this error:

    /usr/sbin/grub-probe: error: failed to get canonical path of `system/root`.

    Any suggestions?

  6. There seems to be issue with chroot unmounting cdrom too early and thus not all paths needed for manual installation are at their places. I am trying to figure workaround but nothing seems to work in UEFI mode. I ended up installing 19.04 and then upgrading to 19.10. :(

  7. note for Ubuntu 20.04: update-grub will not work properly unless you set system/root mountpoint to “/”. You may set it inside chroot, then remount root partition back read/write.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.