openSUSE Tumbleweed Root on ZFS

Overview 

Caution 

This HOWTO uses a whole physical disk.
Do not use these instructions for dual-booting.
Backup your data. Any existing data will be lost.
This is not an openSUSE official HOWTO page. This document will be updated if Root on ZFS support of openSUSE is added in the future. Also, openSUSE’s default system installer Yast2 does not support zfs. The method of setting up system with zypper without Yast2 used in this page is based on openSUSE installation methods written by the experience of the people in the community. For more information about this, please look at the external links.

System Requirements 

64-bit openSUSE Tumbleweed Live CD w/ GUI (e.g. gnome iso)
A 64-bit kernel is strongly encouraged.
Installing on a drive which presents 4 KiB logical sectors (a “4Kn” drive) only works with UEFI booting. This not unique to ZFS. GRUB does not and will not work on 4Kn with legacy (BIOS) booting.

Computers that have less than 2 GiB of memory run ZFS slowly. 4 GiB of memory is recommended for normal performance in basic workloads. If you wish to use deduplication, you will need massive amounts of RAM. Enabling deduplication is a permanent change that cannot be easily reverted.

Support 

If you need help, reach out to the community using the Mailing Lists or IRC at #zfsonlinux on Libera Chat. If you have a bug report or feature request related to this HOWTO, please file a new issue and mention @Zaryob.

Contributing 

Fork and clone: https://github.com/openzfs/openzfs-docs

Install the tools:

sudo zypper install python3-pip
pip3 install -r docs/requirements.txt
# Add ~/.local/bin to your $PATH, e.g. by adding this to ~/.bashrc:
PATH=$HOME/.local/bin:$PATH

Make your changes.

Test:

cd docs
make html
sensible-browser _build/html/index.html

git commit --signoff to a branch, git push, and create a pull request.

Encryption 

This guide supports three different encryption options: unencrypted, ZFS native encryption, and LUKS. With any option, all ZFS features are fully available.

Unencrypted does not encrypt anything, of course. With no encryption happening, this option naturally has the best performance.

ZFS native encryption encrypts the data and most metadata in the root pool. It does not encrypt dataset or snapshot names or properties. The boot pool is not encrypted at all, but it only contains the bootloader, kernel, and initrd. (Unless you put a password in /etc/fstab, the initrd is unlikely to contain sensitive data.) The system cannot boot without the passphrase being entered at the console. Performance is good. As the encryption happens in ZFS, even if multiple disks (mirror or raidz topologies) are used, the data only has to be encrypted once.

LUKS encrypts almost everything. The only unencrypted data is the bootloader, kernel, and initrd. The system cannot boot without the passphrase being entered at the console. Performance is good, but LUKS sits underneath ZFS, so if multiple disks (mirror or raidz topologies) are used, the data has to be encrypted once per disk.

Step 1: Prepare The Install Environment 

Boot the openSUSE Live CD. If prompted, login with the username live and password live. Connect your system to the Internet as appropriate (e.g. join your WiFi network). Open a terminal.

Setup and update the repositories:

sudo zypper addrepo https://download.opensuse.org/repositories/filesystems/openSUSE_Tumbleweed/filesystems.repo
sudo zypper refresh  # Refresh all repositories

Optional: Install and start the OpenSSH server in the Live CD environment:

If you have a second system, using SSH to access the target system can be convenient:
```
sudo zypper install openssh-server
sudo systemctl restart sshd.service
```
Hint: You can find your IP address with ip addr show scope global | grep inet. Then, from your main machine, connect with ssh user@IP.
Disable automounting:

If the disk has been used before (with partitions at the same offsets), previous filesystems (e.g. the ESP) will automount if not disabled:
```
gsettings set org.gnome.desktop.media-handling automount false
```
Become root:
```
sudo -i
```

Install ZFS in the Live CD environment:

zypper install zfs zfs-kmp-default
zypper install gdisk
modprobe zfs

Step 2: Disk Formatting 

Set a variable with the disk name:
```
DISK=/dev/disk/by-id/scsi-SATA_disk1
```
Always use the long /dev/disk/by-id/* aliases with ZFS. Using the /dev/sd* device nodes directly can cause sporadic import failures, especially on systems that have more than one storage pool.

Hints:
- ls -la /dev/disk/by-id will list the aliases.
- Are you doing this in a virtual machine? If your virtual disk is missing from /dev/disk/by-id, use /dev/vda if you are using KVM with virtio; otherwise, read the troubleshooting section.

If you are re-using a disk, clear it as necessary:

If the disk was previously used in an MD array:

zypper install mdadm

# See if one or more MD arrays are active:
cat /proc/mdstat
# If so, stop them (replace ``md0`` as required):
mdadm --stop /dev/md0

# For an array using the whole disk:
mdadm --zero-superblock --force $DISK
# For an array using a partition:
mdadm --zero-superblock --force ${DISK}-part2

Clear the partition table:

sgdisk --zap-all $DISK

If you get a message about the kernel still using the old partition table, reboot and start over (except that you can skip this step).

Partition your disk(s):

Run this if you need legacy (BIOS) booting:
```
sgdisk -a1 -n1:24K:+1000K -t1:EF02 $DISK
```
Run this for UEFI booting (for use now or in the future):
```
sgdisk     -n2:1M:+512M   -t2:EF00 $DISK
```
Run this for the boot pool:
```
sgdisk     -n3:0:+1G      -t3:BF01 $DISK
```
Choose one of the following options:
- Unencrypted or ZFS native encryption:
```
sgdisk     -n4:0:0        -t4:BF00 $DISK
```
- LUKS:
```
sgdisk     -n4:0:0        -t4:8309 $DISK
```
If you are creating a mirror or raidz topology, repeat the partitioning commands for all the disks which will be part of the pool.
Create the boot pool:
```
zpool create \
    -o cachefile=/etc/zfs/zpool.cache \
    -o ashift=12 -d \
    -o feature@async_destroy=enabled \
    -o feature@bookmarks=enabled \
    -o feature@embedded_data=enabled \
    -o feature@empty_bpobj=enabled \
    -o feature@enabled_txg=enabled \
    -o feature@extensible_dataset=enabled \
    -o feature@filesystem_limits=enabled \
    -o feature@hole_birth=enabled \
    -o feature@large_blocks=enabled \
    -o feature@lz4_compress=enabled \
    -o feature@spacemap_histogram=enabled \
    -o feature@zpool_checkpoint=enabled \
    -O acltype=posixacl -O canmount=off -O compression=lz4 \
    -O devices=off -O normalization=formD -O relatime=on -O xattr=sa \
    -O mountpoint=/boot -R /mnt \
    bpool ${DISK}-part3
```
You should not need to customize any of the options for the boot pool.

GRUB does not support all of the zpool features. See spa_feature_names in grub-core/fs/zfs/zfs.c. This step creates a separate boot pool for /boot with the features limited to only those that GRUB supports, allowing the root pool to use any/all features. Note that GRUB opens the pool read-only, so all read-only compatible features are “supported” by GRUB.

Hints:
- If you are creating a mirror topology, create the pool using:
```
zpool create \
    ... \
    bpool mirror \
    /dev/disk/by-id/scsi-SATA_disk1-part3 \
    /dev/disk/by-id/scsi-SATA_disk2-part3
```
- For raidz topologies, replace mirror in the above command with raidz, raidz2, or raidz3 and list the partitions from the additional disks.
- The pool name is arbitrary. If changed, the new name must be used consistently. The bpool convention originated in this HOWTO.
Feature Notes:
- The allocation_classes feature should be safe to use. However, unless one is using it (i.e. a special vdev), there is no point to enabling it. It is extremely unlikely that someone would use this feature for a boot pool. If one cares about speeding up the boot pool, it would make more sense to put the whole pool on the faster disk rather than using it as a special vdev.
- The project_quota feature has been tested and is safe to use. This feature is extremely unlikely to matter for the boot pool.
- The resilver_defer should be safe but the boot pool is small enough that it is unlikely to be necessary.
- The spacemap_v2 feature has been tested and is safe to use. The boot pool is small, so this does not matter in practice.
- As a read-only compatible feature, the userobj_accounting feature should be compatible in theory, but in practice, GRUB can fail with an “invalid dnode type” error. This feature does not matter for /boot anyway.
Create the root pool:

Choose one of the following options:
- Unencrypted:
```
zpool create \
    -o cachefile=/etc/zfs/zpool.cache \
    -o ashift=12 \
    -O acltype=posixacl -O canmount=off -O compression=lz4 \
    -O dnodesize=auto -O normalization=formD -O relatime=on \
    -O xattr=sa -O mountpoint=/ -R /mnt \
    rpool ${DISK}-part4
```
- ZFS native encryption:
```
zpool create \
    -o cachefile=/etc/zfs/zpool.cache \
    -o ashift=12 \
    -O encryption=on \
    -O keylocation=prompt -O keyformat=passphrase \
    -O acltype=posixacl -O canmount=off -O compression=lz4 \
    -O dnodesize=auto -O normalization=formD -O relatime=on \
    -O xattr=sa -O mountpoint=/ -R /mnt \
    rpool ${DISK}-part4
```
- LUKS:
```
zypper install cryptsetup
cryptsetup luksFormat -c aes-xts-plain64 -s 512 -h sha256 ${DISK}-part4
cryptsetup luksOpen ${DISK}-part4 luks1
zpool create \
    -o cachefile=/etc/zfs/zpool.cache \
    -o ashift=12 \
    -O acltype=posixacl -O canmount=off -O compression=lz4 \
    -O dnodesize=auto -O normalization=formD -O relatime=on \
    -O xattr=sa -O mountpoint=/ -R /mnt \
    rpool /dev/mapper/luks1
```
Notes:
- The use of ashift=12 is recommended here because many drives today have 4 KiB (or larger) physical sectors, even though they present 512 B logical sectors. Also, a future replacement drive may have 4 KiB physical sectors (in which case ashift=12 is desirable) or 4 KiB logical sectors (in which case ashift=12 is required).
- Setting -O acltype=posixacl enables POSIX ACLs globally. If you do not want this, remove that option, but later add -o acltype=posixacl (note: lowercase “o”) to the zfs create for /var/log, as journald requires ACLs
- Setting normalization=formD eliminates some corner cases relating to UTF-8 filename normalization. It also implies utf8only=on, which means that only UTF-8 filenames are allowed. If you care to support non-UTF-8 filenames, do not use this option. For a discussion of why requiring UTF-8 filenames may be a bad idea, see The problems with enforced UTF-8 only filenames.
- recordsize is unset (leaving it at the default of 128 KiB). If you want to tune it (e.g. -O recordsize=1M), see these various blog posts.
- Setting relatime=on is a middle ground between classic POSIX atime behavior (with its significant performance impact) and atime=off (which provides the best performance by completely disabling atime updates). Since Linux 2.6.30, relatime has been the default for other filesystems. See RedHat’s documentation for further information.
- Setting xattr=sa vastly improves the performance of extended attributes. Inside ZFS, extended attributes are used to implement POSIX ACLs. Extended attributes can also be used by user-space applications. They are used by some desktop GUI applications. They can be used by Samba to store Windows ACLs and DOS attributes; they are required for a Samba Active Directory domain controller. Note that xattr=sa is Linux-specific. If you move your xattr=sa pool to another OpenZFS implementation besides ZFS-on-Linux, extended attributes will not be readable (though your data will be). If portability of extended attributes is important to you, omit the -O xattr=sa above. Even if you do not want xattr=sa for the whole pool, it is probably fine to use it for /var/log.
- Make sure to include the -part4 portion of the drive path. If you forget that, you are specifying the whole disk, which ZFS will then re-partition, and you will lose the bootloader partition(s).
- ZFS native encryption now defaults to aes-256-gcm.
- For LUKS, the key size chosen is 512 bits. However, XTS mode requires two keys, so the LUKS key is split in half. Thus, -s 512 means AES-256.
- Your passphrase will likely be the weakest link. Choose wisely. See section 5 of the cryptsetup FAQ for guidance.
Hints:
- If you are creating a mirror topology, create the pool using:
```
zpool create \
    ... \
    rpool mirror \
    /dev/disk/by-id/scsi-SATA_disk1-part4 \
    /dev/disk/by-id/scsi-SATA_disk2-part4
```
- For raidz topologies, replace mirror in the above command with raidz, raidz2, or raidz3 and list the partitions from the additional disks.
- When using LUKS with mirror or raidz topologies, use /dev/mapper/luks1, /dev/mapper/luks2, etc., which you will have to create using cryptsetup.
- The pool name is arbitrary. If changed, the new name must be used consistently. On systems that can automatically install to ZFS, the root pool is named rpool by default.

Step 3: System Installation 

Create filesystem datasets to act as containers:
```
zfs create -o canmount=off -o mountpoint=none rpool/ROOT
zfs create -o canmount=off -o mountpoint=none bpool/BOOT
```
On Solaris systems, the root filesystem is cloned and the suffix is incremented for major system changes through pkg image-update or beadm. Similar functionality has been implemented in Ubuntu 20.04 with the zsys tool, though its dataset layout is more complicated. Even without such a tool, the rpool/ROOT and bpool/BOOT containers can still be used for manually created clones. That said, this HOWTO assumes a single filesystem for /boot for simplicity.
Create filesystem datasets for the root and boot filesystems:
```
zfs create -o canmount=noauto -o mountpoint=/ rpool/ROOT/suse
zfs mount rpool/ROOT/suse

zfs create -o mountpoint=/boot bpool/BOOT/suse
```
With ZFS, it is not normally necessary to use a mount command (either mount or zfs mount). This situation is an exception because of canmount=noauto.

Create datasets:

zfs create                                 rpool/home
zfs create -o mountpoint=/root             rpool/home/root
chmod 700 /mnt/root
zfs create -o canmount=off                 rpool/var
zfs create -o canmount=off                 rpool/var/lib
zfs create                                 rpool/var/log
zfs create                                 rpool/var/spool

The datasets below are optional, depending on your preferences and/or software choices.

If you wish to exclude these from snapshots:

zfs create -o com.sun:auto-snapshot=false  rpool/var/cache
zfs create -o com.sun:auto-snapshot=false  rpool/var/tmp
chmod 1777 /mnt/var/tmp

If you use /opt on this system:

zfs create                                 rpool/opt

If you use /srv on this system:

zfs create                                 rpool/srv

If you use /usr/local on this system:

zfs create -o canmount=off                 rpool/usr
zfs create                                 rpool/usr/local

If this system will have games installed:

zfs create                                 rpool/var/games

If this system will store local email in /var/mail:

zfs create                                 rpool/var/spool/mail

If this system will use Snap packages:

zfs create                                 rpool/var/snap

If this system will use Flatpak packages:

zfs create                                 rpool/var/lib/flatpak

If you use /var/www on this system:

zfs create                                 rpool/var/www

If this system will use GNOME:

zfs create                                 rpool/var/lib/AccountsService

If this system will use Docker (which manages its own datasets & snapshots):

zfs create -o com.sun:auto-snapshot=false  rpool/var/lib/docker

If this system will use NFS (locking):

zfs create -o com.sun:auto-snapshot=false  rpool/var/lib/nfs

Mount a tmpfs at /run:

mkdir /mnt/run
mount -t tmpfs tmpfs /mnt/run
mkdir /mnt/run/lock

A tmpfs is recommended later, but if you want a separate dataset for /tmp:

zfs create -o com.sun:auto-snapshot=false  rpool/tmp
chmod 1777 /mnt/tmp

The primary goal of this dataset layout is to separate the OS from user data. This allows the root filesystem to be rolled back without rolling back user data.

If you do nothing extra, /tmp will be stored as part of the root filesystem. Alternatively, you can create a separate dataset for /tmp, as shown above. This keeps the /tmp data out of snapshots of your root filesystem. It also allows you to set a quota on rpool/tmp, if you want to limit the maximum space used. Otherwise, you can use a tmpfs (RAM filesystem) later.

Copy in zpool.cache:

mkdir /mnt/etc/zfs -p
cp /etc/zfs/zpool.cache /mnt/etc/zfs/

Step 4. Install System 

Add repositories into chrooting directory:

zypper --root /mnt ar http://download.opensuse.org/tumbleweed/repo/non-oss/ non-oss
zypper --root /mnt ar http://download.opensuse.org/tumbleweed/repo/oss/ oss

Generate repository indexes:

zypper --root /mnt refresh

You will get fingerprint exception, click a to say always trust and continue.:

New repository or package signing key received:

Repository:       oss
Key Name:         openSUSE Project Signing Key <opensuse@opensuse.org>
Key Fingerprint:  22C07BA5 34178CD0 2EFE22AA B88B2FD4 3DBDC284
Key Created:      Mon May  5 11:37:40 2014
Key Expires:      Thu May  2 11:37:40 2024
Rpm Name:         gpg-pubkey-3dbdc284-53674dd4

Do you want to reject the key, trust temporarily, or trust always? [r/t/a/?] (r):

Install openSUSE Tumbleweed with zypper:

If you install base pattern, zypper will install busybox-grep which masks default kernel package. Thats why I recommend you to install enhanced_base pattern, if you’re new in openSUSE. But in enhanced_base, bloats can annoy you, while you want to use it openSUSE on server. So, you need to select
1. Install base packages of openSUSE Tumbleweed with zypper (Recommended for server):
```
zypper --root /mnt install -t pattern base
```
2. Install enhanced base of openSUSE Tumbleweed with zypper (Recommended for desktop):
```
zypper --root /mnt install -t pattern enhanced_base
```
Install openSUSE zypper package system into chroot:
```
zypper --root /mnt install zypper
```
Recommended: Install openSUSE yast2 system into chroot:
```
zypper --root /mnt install yast2
```

Note

If your /etc/resolv.conf file is empty, proceed this command.

echo “nameserver 8.8.4.4” | tee -a /mnt/etc/resolv.conf

It will make easier to configure network and other configurations for beginners.

To install a desktop environment, see the openSUSE wiki

Step 5: System Configuration 

Configure the hostname:

Replace HOSTNAME with the desired hostname:
```
echo HOSTNAME > /mnt/etc/hostname
vi /mnt/etc/hosts
```
Add a line:
```
127.0.1.1       HOSTNAME
```
or if the system has a real name in DNS:
```
127.0.1.1       FQDN HOSTNAME
```
Hint: Use nano if you find vi confusing.
Copy network information:
```
cp /etc/resolv.conf /mnt/etc
```
You will reconfigure network with yast2.

Note

If your /etc/resolv.conf file is empty, proceed this command.

echo “nameserver 8.8.4.4” | tee -a /mnt/etc/resolv.conf

Bind the virtual filesystems from the LiveCD environment to the new system and chroot into it:

mount --make-private --rbind /dev  /mnt/dev
mount --make-private --rbind /proc /mnt/proc
mount --make-private --rbind /sys  /mnt/sys
mount -t tmpfs tmpfs /mnt/run
mkdir /mnt/run/lock

chroot /mnt /usr/bin/env DISK=$DISK bash --login

Note: This is using --rbind, not --bind.

Configure a basic system environment:
```
ln -s /proc/self/mounts /etc/mtab
zypper refresh
```
Even if you prefer a non-English system language, always ensure that en_US.UTF-8 is available:
```
locale -a
```
Output must include that languages:
- C
- C.UTF-8
- en_US.utf8
- POSIX
Find yout locale from locale -a commands output then set it with following command.
```
localectl set-locale LANG=en_US.UTF-8
```
Optional: Reinstallation for stability:

After installation it may need. Some packages may have minor errors. For that, do this if you wish. Since there is no command like dpkg-reconfigure in openSUSE, zypper install -f stated as a alternative for it but it will reinstall packages.
```
zypper install -f permissions-config iputils ca-certificates  ca-certificates-mozilla pam shadow dbus-1 libutempter0 suse-module-tools util-linux
```
Install kernel:
```
zypper install kernel-default kernel-firmware
```
Note

If you installed base pattern, you need to deinstall busybox-grep to install kernel-default package.

Install ZFS in the chroot environment for the new system:

zypper addrepo https://download.opensuse.org/repositories/filesystems/openSUSE_Tumbleweed/filesystems.repo
zypper refresh   # Refresh all repositories
zypper install zfs

For LUKS installs only, setup /etc/crypttab:
```
zypper install cryptsetup

echo luks1 /dev/disk/by-uuid/$(blkid -s UUID -o value ${DISK}-part4) none \
    luks,discard,initramfs > /etc/crypttab
```
The use of initramfs is a work-around for cryptsetup does not support ZFS.

Hint: If you are creating a mirror or raidz topology, repeat the /etc/crypttab entries for luks2, etc. adjusting for each disk.

For LUKS installs only, fix cryptsetup naming for ZFS:

echo 'ENV{DM_NAME}!="", SYMLINK+="$env{DM_NAME}"
ENV{DM_NAME}!="", SYMLINK+="dm-name-$env{DM_NAME}"' >> /etc/udev/rules.d/99-local-crypt.rules

Install GRUB

Choose one of the following options:
- Install GRUB for legacy (BIOS) booting:
```
zypper install grub2-i386-pc
```
- Install GRUB for UEFI booting:
```
zypper install grub2-x86_64-efi dosfstools os-prober
mkdosfs -F 32 -s 1 -n EFI ${DISK}-part2
mkdir /boot/efi
echo /dev/disk/by-uuid/$(blkid -s PARTUUID -o value ${DISK}-part2) \
   /boot/efi vfat defaults 0 0 >> /etc/fstab
mount /boot/efi
```
  Notes:
  - The -s 1 for mkdosfs is only necessary for drives which present
    4 KiB logical sectors (“4Kn” drives) to meet the minimum cluster size (given the partition size of 512 MiB) for FAT32. It also works fine on drives which present 512 B sectors.
  - For a mirror or raidz topology, this step only installs GRUB on the
    first disk. The other disk(s) will be handled later.
Optional: Remove os-prober:
```
zypper remove os-prober
```
This avoids error messages from update-bootloader. os-prober is only necessary in dual-boot configurations.
Set a root password:
```
passwd
```

Enable importing bpool

This ensures that bpool is always imported, regardless of whether /etc/zfs/zpool.cache exists, whether it is in the cachefile or not, or whether zfs-import-scan.service is enabled.

vi /etc/systemd/system/zfs-import-bpool.service

[Unit]
DefaultDependencies=no
Before=zfs-import-scan.service
Before=zfs-import-cache.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/sbin/zpool import -N -o cachefile=none bpool
# Work-around to preserve zpool cache:
ExecStartPre=-/bin/mv /etc/zfs/zpool.cache /etc/zfs/preboot_zpool.cache
ExecStartPost=-/bin/mv /etc/zfs/preboot_zpool.cache /etc/zfs/zpool.cache

[Install]
WantedBy=zfs-import.target

systemctl enable zfs-import-bpool.service

Optional (but recommended): Mount a tmpfs to /tmp

If you chose to create a /tmp dataset above, skip this step, as they are mutually exclusive choices. Otherwise, you can put /tmp on a tmpfs (RAM filesystem) by enabling the tmp.mount unit.
```
cp /usr/share/systemd/tmp.mount /etc/systemd/system/
systemctl enable tmp.mount
```

Step 6: Kernel Installation 

Add zfs module into dracut:

echo 'zfs'>> /etc/modules-load.d/zfs.conf

Refresh kernel files:

kernel-install add $(uname -r) /boot/vmlinuz-$(uname -r)

Refresh the initrd files:
```
mkinitrd
```
Note: After some installations, LUKS partition cannot seen by dracut, this will print “Failure occured during following action: configuring encrypted DM device X VOLUME_CRYPTSETUP_FAILED“. For fix this issue you need to check cryptsetup installation. See for more information Note: Although we add the zfs config to the system module into /etc/modules.d, if it is not seen by dracut, we have to add it to dracut by force. dracut –kver $(uname -r) –force –add-drivers “zfs”

Step 7: Grub2 Installation 

Verify that the ZFS boot filesystem is recognized:
```
grub2-probe /boot
```
Output must be zfs

If you having trouble with grub2-probe command make this:

echo 'export ZPOOL_VDEV_NAME_PATH=YES' >> /etc/profile
export ZPOOL_VDEV_NAME_PATH=YES

then go back to grub2-probe step.

Workaround GRUB’s missing zpool-features support:

vi /etc/default/grub
# Set: GRUB_CMDLINE_LINUX="root=ZFS=rpool/ROOT/suse"

Optional (but highly recommended): Make debugging GRUB easier:
```
vi /etc/default/grub
# Remove quiet from: GRUB_CMDLINE_LINUX_DEFAULT
# Uncomment: GRUB_TERMINAL=console
# Save and quit.
```
Later, once the system has rebooted twice and you are sure everything is working, you can undo these changes, if desired.
Update the boot configuration:
```
update-bootloader
```
Note: Ignore errors from osprober, if present. Note: If you have had trouble with the grub2 installation, I suggest you use systemd-boot. Note: If this command don’t gives any output, use classic grub.cfg generation with following command: grub2-mkconfig -o /boot/grub2/grub.cfg
Install the boot loader:
1. For legacy (BIOS) booting, install GRUB to the MBR:
```
grub2-install $DISK
```
Note that you are installing GRUB to the whole disk, not a partition.

If you are creating a mirror or raidz topology, repeat the grub-install command for each disk in the pool.
1. For UEFI booting, install GRUB to the ESP:
```
grub2-install --target=x86_64-efi --efi-directory=/boot/efi \
    --bootloader-id=opensuse --recheck --no-floppy
```
  It is not necessary to specify the disk here. If you are creating a mirror or raidz topology, the additional disks will be handled later.

Step 8: Systemd-Boot Installation 

Warning: This will break your Yast2 Bootloader Configuration. Make sure that you are not able to fix the problem you are having with grub2. I decided to write this part because sometimes grub2 doesn’t see the rpool pool in some cases.

Install systemd-boot:
```
bootctl install
```

Configure bootloader configuration:

tee -a /boot/efi/loader/loader.conf << EOF
default openSUSE_Tumbleweed.conf
timeout 5
console-mode auto
EOF

Write Entries:

tee -a /boot/efi/loader/entries/openSUSE_Tumbleweed.conf << EOF
title   openSUSE Tumbleweed
linux   /EFI/openSUSE/vmlinuz
initrd  /EFI/openSUSE/initrd
options root=zfs=rpool/ROOT/suse boot=zfs
EOF

Copy files into EFI:

mkdir /boot/efi/EFI/openSUSE
cp /boot/{vmlinuz,initrd} /boot/efi/EFI/openSUSE

Update systemd-boot variables:
```
bootctl update
```

Step 9: Filesystem Configuration 

Fix filesystem mount ordering:

We need to activate zfs-mount-generator. This makes systemd aware of the separate mountpoints, which is important for things like /var/log and /var/tmp. In turn, rsyslog.service depends on var-log.mount by way of local-fs.target and services using the PrivateTmp feature of systemd automatically use After=var-tmp.mount.
```
mkdir /etc/zfs/zfs-list.cache
touch /etc/zfs/zfs-list.cache/bpool
touch /etc/zfs/zfs-list.cache/rpool
ln -s /usr/lib/zfs/zed.d/history_event-zfs-list-cacher.sh /etc/zfs/zed.d
zed -F &
```
Verify that zed updated the cache by making sure these are not empty:
```
cat /etc/zfs/zfs-list.cache/bpool
cat /etc/zfs/zfs-list.cache/rpool
```
If either is empty, force a cache update and check again:
```
zfs set canmount=on     bpool/BOOT/suse
zfs set canmount=noauto rpool/ROOT/suse
```
If they are still empty, stop zed (as below), start zed (as above) and try again.

Stop zed:
```
fg
Press Ctrl-C.
```
Fix the paths to eliminate /mnt:
```
sed -Ei "s|/mnt/?|/|" /etc/zfs/zfs-list.cache/*
```

Step 10: First Boot 

Optional: Install SSH:

zypper install --yes openssh-server

vi /etc/ssh/sshd_config
# Set: PermitRootLogin yes

Optional: Snapshot the initial installation:
```
zfs snapshot bpool/BOOT/suse@install
zfs snapshot rpool/ROOT/suse@install
```
In the future, you will likely want to take snapshots before each upgrade, and remove old snapshots (including this one) at some point to save space.
Exit from the chroot environment back to the LiveCD environment:
```
exit
```

Run these commands in the LiveCD environment to unmount all filesystems:

mount | grep -v zfs | tac | awk '/\/mnt/ {print $3}' | \
    xargs -i{} umount -lf {}
zpool export -a

Reboot:
```
reboot
```
Wait for the newly installed system to boot normally. Login as root.

Create a user account:

Replace username with your desired username:

zfs create rpool/home/username
adduser username

cp -a /etc/skel/. /home/username
chown -R username:username /home/username
usermod -a -G audio,cdrom,dip,floppy,netdev,plugdev,sudo,video username

Mirror GRUB

If you installed to multiple disks, install GRUB on the additional disks.
- For legacy (BIOS) booting:: Check to be sure we using efi mode:
```
efibootmgr -v
```
  This must return a message contains legacy_boot
  
  Then reconfigure grub:
```
grub-install $DISK
```
  Hit enter until you get to the device selection screen. Select (using the space bar) all of the disks (not partitions) in your pool.
- For UEFI booting:
```
umount /boot/efi
```
  For the second and subsequent disks (increment debian-2 to -3, etc.):
```
dd if=/dev/disk/by-id/scsi-SATA_disk1-part2 \
   of=/dev/disk/by-id/scsi-SATA_disk2-part2
efibootmgr -c -g -d /dev/disk/by-id/scsi-SATA_disk2 \
    -p 2 -L "opensuse-2" -l '\EFI\opensuse\grubx64.efi'

mount /boot/efi
```

Step 11: Optional: Configure Swap 

Caution: On systems with extremely high memory pressure, using a zvol for swap can result in lockup, regardless of how much swap is still available. There is a bug report upstream.

Create a volume dataset (zvol) for use as a swap device:
```
zfs create -V 4G -b $(getconf PAGESIZE) -o compression=zle \
    -o logbias=throughput -o sync=always \
    -o primarycache=metadata -o secondarycache=none \
    -o com.sun:auto-snapshot=false rpool/swap
```
You can adjust the size (the 4G part) to your needs.

The compression algorithm is set to zle because it is the cheapest available algorithm. As this guide recommends ashift=12 (4 kiB blocks on disk), the common case of a 4 kiB page size means that no compression algorithm can reduce I/O. The exception is all-zero pages, which are dropped by ZFS; but some form of compression has to be enabled to get this behavior.
Configure the swap device:

Caution: Always use long /dev/zvol aliases in configuration files. Never use a short /dev/zdX device name.
```
mkswap -f /dev/zvol/rpool/swap
echo /dev/zvol/rpool/swap none swap discard 0 0 >> /etc/fstab
echo RESUME=none > /etc/initramfs-tools/conf.d/resume
```
The RESUME=none is necessary to disable resuming from hibernation. This does not work, as the zvol is not present (because the pool has not yet been imported) at the time the resume script runs. If it is not disabled, the boot process hangs for 30 seconds waiting for the swap zvol to appear.
Enable the swap device:
```
swapon -av
```

Step 12: Final Cleanup 

Wait for the system to boot normally. Login using the account you created. Ensure the system (including networking) works normally.

Optional: Delete the snapshots of the initial installation:

sudo zfs destroy bpool/BOOT/suse@install
sudo zfs destroy rpool/ROOT/suse@install

Optional: Disable the root password:
```
sudo usermod -p '*' root
```
Optional (but highly recommended): Disable root SSH logins:

If you installed SSH earlier, revert the temporary change:
```
vi /etc/ssh/sshd_config
# Remove: PermitRootLogin yes

systemctl restart sshd
```
Optional: Re-enable the graphical boot process:

If you prefer the graphical boot process, you can re-enable it now. If you are using LUKS, it makes the prompt look nicer.
```
sudo vi /etc/default/grub
# Add quiet to GRUB_CMDLINE_LINUX_DEFAULT
# Comment out GRUB_TERMINAL=console
# Save and quit.

sudo update-bootloader
```
Note: Ignore errors from osprober, if present.
Optional: For LUKS installs only, backup the LUKS header:
```
sudo cryptsetup luksHeaderBackup /dev/disk/by-id/scsi-SATA_disk1-part4 \
    --header-backup-file luks1-header.dat
```
Store that backup somewhere safe (e.g. cloud storage). It is protected by your LUKS passphrase, but you may wish to use additional encryption.

Hint: If you created a mirror or raidz topology, repeat this for each LUKS volume (luks2, etc.).

Troubleshooting 

Rescuing using a Live CD 

Go through Step 1: Prepare The Install Environment.

For LUKS, first unlock the disk(s):

zypper install cryptsetup
cryptsetup luksOpen /dev/disk/by-id/scsi-SATA_disk1-part4 luks1
# Repeat for additional disks, if this is a mirror or raidz topology.

Mount everything correctly:

zpool export -a
zpool import -N -R /mnt rpool
zpool import -N -R /mnt bpool
zfs load-key -a
zfs mount rpool/ROOT/suse
zfs mount -a

If needed, you can chroot into your installed environment:

mount --make-private --rbind /dev  /mnt/dev
mount --make-private --rbind /proc /mnt/proc
mount --make-private --rbind /sys  /mnt/sys
chroot /mnt /bin/bash --login
mount /boot/efi
mount -a

Do whatever you need to do to fix your system.

When done, cleanup:

exit
mount | grep -v zfs | tac | awk '/\/mnt/ {print $3}' | \
    xargs -i{} umount -lf {}
zpool export -a
reboot

Areca 

Systems that require the arcsas blob driver should add it to the /etc/initramfs-tools/modules file and run update-initramfs -c -k all.

Upgrade or downgrade the Areca driver if something like RIP: 0010:[<ffffffff8101b316>] [<ffffffff8101b316>] native_read_tsc+0x6/0x20 appears anywhere in kernel log. ZoL is unstable on systems that emit this error message.

MPT2SAS 

Most problem reports for this tutorial involve mpt2sas hardware that does slow asynchronous drive initialization, like some IBM M1015 or OEM-branded cards that have been flashed to the reference LSI firmware.

The basic problem is that disks on these controllers are not visible to the Linux kernel until after the regular system is started, and ZoL does not hotplug pool members. See https://github.com/zfsonlinux/zfs/issues/330.

Most LSI cards are perfectly compatible with ZoL. If your card has this glitch, try setting ZFS_INITRD_PRE_MOUNTROOT_SLEEP=X in /etc/default/zfs. The system will wait X seconds for all drives to appear before importing the pool.

QEMU/KVM/XEN 

Set a unique serial number on each virtual disk using libvirt or qemu (e.g. -drive if=none,id=disk1,file=disk1.qcow2,serial=1234567890).

To be able to use UEFI in guests (instead of only BIOS booting), run this on the host:

sudo zypper install ovmf
sudo vi /etc/libvirt/qemu.conf

Uncomment these lines:

nvram = [
   "/usr/share/OVMF/OVMF_CODE.fd:/usr/share/OVMF/OVMF_VARS.fd",
   "/usr/share/OVMF/OVMF_CODE.secboot.fd:/usr/share/OVMF/OVMF_VARS.fd",
   "/usr/share/AAVMF/AAVMF_CODE.fd:/usr/share/AAVMF/AAVMF_VARS.fd",
   "/usr/share/AAVMF/AAVMF32_CODE.fd:/usr/share/AAVMF/AAVMF32_VARS.fd"
]

sudo systemctl restart libvirtd.service

VMware 

Set disk.EnableUUID = "TRUE" in the vmx file or vsphere configuration. Doing this ensures that /dev/disk aliases are created in the guest.