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How to Install Fedora 38/39 with Snapshot and Rollback Support

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Madhu Desai
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81 comments on How to Install Fedora 38/39 with Snapshot and Rollback Support

Fedora Linux 39 has been released! Fedora 39 brings numerous performance and security improvements, as well as hardware support. This release also includes the latest Gnome 45 desktop with improved styling.

In this guide, I will show you how to install Fedora 39 with the btrfs file system, as well as snapshot and rollback support. As a result, if you make a mistake with system configuration changes, package installations, or updates, you won't have to worry about losing data. Simply restore the snapshot before your problematic change, and you'll be fine.

I have updated this post for Fedora 39, which was originally intended for Fedora 38. In terms of btrfs snapshot and rollback support, nothing has changed between Fedora 38 and Fedora 39.

In case you've already followed a previous version of this tutorial and want to upgrade to Fedora 39, go straight to the section on upgrading at the end of this article and upgrade from Fedora 38 to Fedora 39. You don't have to do anything else.

Here’s a quick rundown of what needs to be done:

  1. Install Fedora 39 Workstation with btrfs file system by creating a main volume for the system root and a subvolume for the home.
  2. After the installation is complete, create additional subvolumes on the system root. These additional subvolumes will be created to keep certain directories out of the rollback regime. Some of these directories contain temporary files and caches, others contain data that you do not want to lose if you roll back the system root, and some should be in Read-Write mode when booting into a Read-only snapshot.
  3. Install and configure the snapper tool so that you can create, delete, and compare snapshots, as well as undo changes made between snapshots.
  4. Install and configure the grub-btrfs tool so that you can boot to any snapshot from the GRUB menu.
  5. Take a subvolume snapshot of the main volume and set the subvolume as the default '/' file system to make rollback much easier when using the snapper tool.
  6. And finally, enable automatic timeline snapshots of the '/' file system using the snapper tool.

If you want to install Fedora 38 with LUKS Full Disk Encryption, Snapshot and Rollback Support, please see my other article, How to Install Fedora 38/39 with Full Disk Encryption, Snapshot and Rollback Support.

So let's get started.

Table of Contents

1. Disk and Subvolumes Layout for Fedora

I'll use a hard disk with a capacity of 100 GIB. Fedora 39 suggests that the ESP be at least 500 MiB in size. So I'll create a 512 MiB EFI System Partition. You can, however, increase the size if necessary. I'll create a btrfs volume with the remaining disk space. Fedora creates a SwapOnZRAM during boot, so no separate swap partition is required.

This is how the disk partition looks.

NAME           SIZE   FSTYPE  LABEL    MOUNTPOINT
/dev/vda       100G
├─/dev/vda1    512M   vfat    EFI      /boot/efi
└─/dev/vda2   99.5G   btrfs   FEDORA   /

I will be installing the system root on the btrfs main volume (/dev/vda2). Then, on the system root, I'll create the following subvolumes to keep them out of root file system snapshots. In the end, this is how the disk layout looks.

NAME              MOUNTPOINT                 TYPE
[main]            /                          mainvolume
home              /home                      subvolume
opt               /opt                       subvolume
cache             /var/cache                 subvolume
crash             /var/crash                 subvolume
log               /var/log                   subvolume
spool             /var/spool                 subvolume
tmp               /var/tmp                   subvolume
www               /var/www                   subvolume
AccountsService   /var/lib/AccountsService   subvolume
gdm               /var/lib/gdm               subvolume
images            /var/lib/libvirt/images    subvolume
.mozilla          /home/$USER/.mozilla       subvolume

The directories for which subvolumes are created and the reasons for doing so are listed below.

/home

Contains user data. It is created to keep user data separate and also to avoid loss of user data on system root rollbacks. To learn more about /home, check this link: /home.

/opt

Contains applications installed by a third party. It is excluded to prevent these applications from being uninstalled during rollbacks. To learn more about /opt, check this link: /opt.

/var/cache, /var/crash, /var/tmp

Directories contain temporary files and caches. So they are created to be excluded from snapshots. Fedora also mounts /tmp with tmpfs at boot, so a separate subvolume for /tmp is unnecessary. To learn more, check these links: /var/cache, /var/crash, /var/tmp, /tmp.

/var/log

Contains log files. It is created to avoid the loss of log data during rollbacks. To learn more about /var/log, check this link: /var/log.

/var/spool

Contains data that is awaiting some kind of later processing such as mail, mail queues, printing, printer spool, and so on. Created to avoid a loss of mail, printing, and spool data after a rollback. To learn more about /var/spool, check this link: /var/spool.

/var/www

Web server directory. It is created to keep hosted web server data separate and to avoid data loss on system root rollbacks.

/var/lib/AccountsService, /var/lib/gdm

Contains login user and Gnome display information. These directories must be writable at all times. When you try to boot a snapshot from the GRUB menu, you are booting into a read-only snapshot, which causes the system to hang just before the Gnome login screen appears.

In case you're using a desktop environment other than Gnome, it's necessary to replace the '/var/lib/gdm' with one that's specific to your desktop environment.

For KDE, it is '/var/lib/sddm'.

For XFCE, it might be '/var/lib/lightdm' and '/var/lib/lightdm-data'. I haven't tested.

To find out about other desktop environments, refer to this page.

/var/lib/libvirt/images

The default location for libvirt-managed virtual machine images. Excluded to avoid replacing virtual machine images with older versions during a rollback.

/home/$USER/.mozilla

By default, Fedora Workstation includes the Firefox browser. If you take a snapshot of your home directory and later undo any changes, you don't want to lose any new bookmarks, passwords, and other user data.

So, I'll create a new subvolume for the '.mozilla' directory. This keeps it separate from the home subvolume and prevents data loss during undo operations.

If you use the Chrome web browser, create a subvolume for the '/home/$USER/.config/google-chrome' directory.

Depending on your usage, you may also want to consider creating subvolumes in your home directory for the following directories:

  • GnuPG: /home/$USER/.gnupg
  • SSH: /home/$USER/.ssh
  • Thunderbird Mail: /home/$USER/.thunderbird

2. Install Fedora Workstation

Boot your system using the Fedora 39 Workstation installer in UEFI mode. On the welcome screen, select the Install to Hard Drive option. Next, select your Language, Keyboard, and configure Time & Date. Following that, from the INSTALLATION SUMMARY screen, select Installation Destination.

You should now be on the INSTALLATION DESTINATION screen. To proceed, pick the Advanced Custom (Blivet-GUI) radio button and then hit the Done button.

On the BLIVET GUI PARTITIONING screen, create the partitions, file systems, and btrfs subvolumes necessary to install the Fedora 39 Workstation.

Install Fedora with Snapshot and Rollback Support - Blivet

First, you need to create and mount the EFI partition. Select the free space and click the + sign to create a partition.

Set the partition Size to 512 MiB, the Filesystem to EFI System Partition, and the Mountpoint to /boot/efi.

Install Fedora with Snapshot and Rollback Support - EFI Partition

Then, you need to create a btrfs volume where you can create all the subvolumes needed to install Fedora 39 Workstation.

Select the free space again and click on the + sign to create a Btrfs volume. Set the Filesystem to btrfs and the Mountpoint to /. I used the entire remaining space. However, you can specify the size you want for the btrfs volume.

Install Fedora with Snapshot and Rollback Support - BTRFS root partition

Next, you must create a home subvolume. (1) Select the Btrfs Volume from the left panel, and (2) click on the + sign on the right panel.

Install Fedora with Snapshot and Rollback Support - Create Subvolume

Create a home subvolume. Enter the Name as home and Mountpoint as /home. Click OK to finish.

Install Fedora with Snapshot and Rollback Support - Home Subvolume

I will create the remaining subvolumes when the installation is finished. This is because the Anaconda installer does not allow you to create subvolumes with slashes (/) in their names, such as var/log.

For now, click Done to finish creating subvolumes.

On the SUMMARY OF CHANGES screen, double-check that everything is properly defined. To finalize the changes, click the Accept Changes button.

Install Fedora with Snapshot and Rollback Support - Summary

You will be returned to the INSTALLATION SUMMARY screen. Press the Begin Installation button to start the installation process. The installation process will start. Just sit back and relax.

Install Fedora with Snapshot and Rollback Support - Installation

When the installation is finished, click the Finish Installation button and restart the system.

The last phase of the installation process will start. Click the Start Setup button to complete the remaining customization steps, such as setting a new login, password, etc.

You will then be logged into the Fedora 39 Workstation with the all-new Gnome 45 desktop interface.

Install Fedora with Snapshot and Rollback Support - Gnome 45

When booting your system, you may have noticed the following error message.

error: ../../grub-core/commands/loadenv.c:216:sparse file not allowed.

This is because you did not create a separate ext4 /boot partition and instead included it in the btrfs system root. GRUB preboot writes to /boot/grub2/grubenv if the boot was successful. This error occurs because of the GRUB btrfs.mod driver, unlike ext4, is read-only. To resolve this, open the Gnome terminal and execute the following command.

$ sudo grub2-editenv - unset menu_auto_hide

Set the btrfs volume label. I named the btrfs volume FEDORA, but you may name it whatever you want.

$ sudo btrfs filesystem label / FEDORA

$ sudo btrfs filesystem show /
Label: 'FEDORA'  uuid: ca244df3-0ddb-45c6-bd99-077d9bd81b04
	Total devices 1 FS bytes used 5.82GiB
	devid    1 size 99.50GiB used 10.02GiB path /dev/vda2

Your setup should look something like this.

$ lsblk -p
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
/dev/zram0  251:0    0  3.8G  0 disk [SWAP]
/dev/vda    252:0    0  100G  0 disk 
├─/dev/vda1 252:1    0  512M  0 part /boot/efi
└─/dev/vda2 252:2    0 99.5G  0 part /home
                                     /

And the subvolumes will look like this.

$ sudo btrfs subvolume list /
ID 256 gen 41 top level 5 path home
ID 257 gen 33 top level 5 path var/lib/machines

The var/lib/machines subvolume is created by systemd implicitly in Fedora Workstation for systemd-nspawn containers.

Enable the fastest mirrors to speed up package downloads. Copy the command from sudo to EOF, paste it into your terminal, and hit <Enter>.

$ sudo bash -c 'cat >> /etc/dnf/dnf.conf' <<EOF
defaultyes=True
fastestmirror=True
max_parallel_downloads=10
EOF

Clear all previous caches and update the local DNF metadata cache.

$ sudo dnf clean all
$ sudo dnf makecache

Install the packages listed below.

$ sudo dnf install vim inotify-tools make

Now, update your operating system.

$ sudo dnf update

And reboot your system.

$ sudo reboot

3. Create the Additional Subvolumes

I'll now proceed to create the remaining subvolumes on the system root. As previously stated, these subvolumes are created on the system root to avoid being included in the rollback regime because some of these directories contain temporary files and caches, others contain data that you do not want to lose if you rollback the system root, and some should be in Read-Write mode when booting into a Read-only snapshot.

Instead of manually creating subvolumes, I use the bash for loop. If you want to add or remove subvolumes, modify the SUBVOLUMES variable declaration.

#### Get the UUID of your btrfs system root.
$ ROOT_UUID="$(sudo grub2-probe --target=fs_uuid /)"

$ echo $ROOT_UUID
ca244df3-0ddb-45c6-bd99-077d9bd81b04

#### Get the btrfs subvolume mount options from your fstab.
$ OPTIONS="$(grep '/home' /etc/fstab | awk '{print $4}' | cut -d, -f2-)"

$ echo $OPTIONS
compress=zstd:1

#### Create a directory path. Only for other DEs; not required for Fedora Workstation.
$ sudo mkdir -vp /var/lib/libvirt

#### Declare rest of the subvolumes you want to create in the array.
#### Copy from 'SUBVOLUMES' to ')', paste it in terminal, and hit <Enter>.
$ SUBVOLUMES=(
    "opt"
    "var/cache"
    "var/crash"
    "var/log"
    "var/spool"
    "var/tmp"
    "var/www"
    "var/lib/AccountsService"
    "var/lib/gdm"
    "var/lib/libvirt/images"
    "home/$USER/.mozilla"
)

$ echo ${SUBVOLUMES[@]}
opt var/cache var/crash var/log var/spool var/tmp var/www var/lib/AccountsService var/lib/gdm var/lib/libvirt/images home/madhu/.mozilla

#### Run the for loop to create the subvolumes.
#### Copy from 'for' to 'done', paste it in terminal, and hit <Enter>.
$ for dir in "${SUBVOLUMES[@]}" ; do
    if [[ -d "/${dir}" ]] ; then
        sudo mv -v "/${dir}" "/${dir}-old"
        sudo btrfs subvolume create "/${dir}"
        sudo cp -ar "/${dir}-old/." "/${dir}/"
    else
        sudo btrfs subvolume create "/${dir}"
    fi
    sudo restorecon -RF "/${dir}"
    printf "%-41s %-24s %-5s %-s %-s\n" \
        "UUID=${ROOT_UUID}" \
        "/${dir}" \
        "btrfs" \
        "subvol=${dir},${OPTIONS}" \
        "0 0" | \
        sudo tee -a /etc/fstab
done

Ensure that you are the owner of the .mozilla directory.

$ sudo chown -R $USER: /home/$USER/.mozilla

$ ls -ldh /home/$USER/.mozilla
drwxr-xr-x. 1 madhu madhu 34 Nov  1 06:35 /home/madhu/.mozilla

Examine your /etc/fstab file. This is what it should look like. The UUID and username will be unique to your system.

$ cat /etc/fstab
...
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /                        btrfs defaults        0 0
UUID=39A2-F9C9                            /boot/efi                vfat  umask=0077,shortname=winnt 0 2
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /home                    btrfs subvol=home,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /opt                     btrfs subvol=opt,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/cache               btrfs subvol=var/cache,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/crash               btrfs subvol=var/crash,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/log                 btrfs subvol=var/log,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/spool               btrfs subvol=var/spool,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/tmp                 btrfs subvol=var/tmp,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/www                 btrfs subvol=var/www,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/lib/AccountsService btrfs subvol=var/lib/AccountsService,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/lib/gdm             btrfs subvol=var/lib/gdm,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /var/lib/libvirt/images  btrfs subvol=var/lib/libvirt/images,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /home/madhu/.mozilla     btrfs subvol=home/madhu/.mozilla,compress=zstd:1 0 0

Reload /etc/fstab to mount all the subvolumes.

$ sudo systemctl daemon-reload

$ sudo mount -va
/                        : ignored
/boot/efi                : already mounted
/home                    : already mounted
/opt                     : successfully mounted
/var/cache               : successfully mounted
/var/crash               : successfully mounted
/var/log                 : successfully mounted
/var/spool               : successfully mounted
/var/tmp                 : successfully mounted
/var/www                 : successfully mounted
/var/lib/AccountsService : successfully mounted
/var/lib/gdm             : successfully mounted
/var/lib/libvirt/images  : successfully mounted
/home/madhu/.mozilla     : successfully mounted

Check your subvolumes.

$ sudo btrfs subvolume list /
ID 256 gen 123 top level 5 path home
ID 257 gen 123 top level 5 path var/lib/machines
ID 258 gen 104 top level 5 path opt
ID 259 gen 123 top level 5 path var/cache
ID 260 gen 106 top level 5 path var/crash
ID 261 gen 123 top level 5 path var/log
ID 262 gen 123 top level 5 path var/spool
ID 263 gen 123 top level 5 path var/tmp
ID 264 gen 110 top level 5 path var/www
ID 265 gen 123 top level 5 path var/lib/AccountsService
ID 266 gen 123 top level 5 path var/lib/gdm
ID 267 gen 123 top level 5 path var/lib/libvirt/images
ID 268 gen 123 top level 256 path home/madhu/.mozilla

Your setup should now look somewhat like this.

$ lsblk -p
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
/dev/zram0  251:0    0  3.8G  0 disk [SWAP]
/dev/vda    252:0    0  100G  0 disk 
├─/dev/vda1 252:1    0  512M  0 part /boot/efi
└─/dev/vda2 252:2    0 99.5G  0 part /home/madhu/.mozilla
                                     /var/lib/libvirt/images
                                     /var/lib/gdm
                                     /var/lib/AccountsService
                                     /var/www
                                     /var/tmp
                                     /var/spool
                                     /var/log
                                     /var/crash
                                     /var/cache
                                     /opt
                                     /home
                                     /

Now that everything appears to be in order, you can delete the old directories. Copy from 'for' to 'done', paste it into the terminal, and hit <Enter>.

$ for dir in "${SUBVOLUMES[@]}" ; do
    if [[ -d "/${dir}-old" ]] ; then
        sudo rm -rvf "/${dir}-old"
    fi
done

All subvolumes have now been created.

4. Install and Configure Snapper

Install snapper and the optional package python3-dnf-plugin-snapper. The python3-dnf-plugin-snapper package allows you to create pre and post snapshots every time you install a package on the system with the dnf package manager.

$ sudo dnf install snapper python3-dnf-plugin-snapper

Create new snapper configurations named root and home for the btrfs volume at / and /home, respectively.

$ sudo snapper -c root create-config /
$ sudo snapper -c home create-config /home

The snapper configuration files will be saved in the /etc/snapper/configs/ directory.

Verify the snapper configuration files have been created.

$ sudo snapper list-configs
Config | Subvolume
-------+----------
home   | /home    
root   | /

Allow regular user to use snapper without requiring root privileges. Add your user name to the snapper's root and home configurations to set the ACL on the /.snapshots and /home/.snapshots directories.

$ sudo snapper -c root set-config ALLOW_USERS=$USER SYNC_ACL=yes
$ sudo snapper -c home set-config ALLOW_USERS=$USER SYNC_ACL=yes

Add the newly created snapshot subvolumes to the /etc/fstab file. The updated lines are in amber.

$ sudo vim /etc/fstab 
...
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /home/madhu/.mozilla     btrfs subvol=home/madhu/.mozilla,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /.snapshots              btrfs subvol=.snapshots,compress=zstd:1 0 0
UUID=ca244df3-0ddb-45c6-bd99-077d9bd81b04 /home/.snapshots         btrfs subvol=home/.snapshots,compress=zstd:1 0 0

Reload the /etc/fstab file.

$ sudo systemctl daemon-reload
$ sudo mount -va

Your setup should look something like this.

$ lsblk -p /dev/vda
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
/dev/vda    252:0    0  100G  0 disk 
├─/dev/vda1 252:1    0  512M  0 part /boot/efi
└─/dev/vda2 252:2    0 99.5G  0 part /home/.snapshots
                                     /.snapshots
                                     /home/madhu/.mozilla
                                     /var/www
                                     /var/spool
                                     /var/tmp
                                     /var/log
                                     /var/lib/libvirt/images
                                     /var/lib/gdm
                                     /var/lib/AccountsService
                                     /var/crash
                                     /var/cache
                                     /opt
                                     /home
                                     /

And your subvolumes will look like this.

$ sudo btrfs subvolume list /
ID 256 gen 129 top level 5 path home
ID 257 gen 123 top level 5 path var/lib/machines
ID 258 gen 104 top level 5 path opt
ID 259 gen 127 top level 5 path var/cache
ID 260 gen 106 top level 5 path var/crash
ID 261 gen 131 top level 5 path var/log
ID 262 gen 123 top level 5 path var/spool
ID 263 gen 126 top level 5 path var/tmp
ID 264 gen 110 top level 5 path var/www
ID 265 gen 123 top level 5 path var/lib/AccountsService
ID 266 gen 123 top level 5 path var/lib/gdm
ID 267 gen 123 top level 5 path var/lib/libvirt/images
ID 268 gen 123 top level 256 path home/madhu/.mozilla
ID 269 gen 129 top level 5 path .snapshots
ID 270 gen 129 top level 256 path home/.snapshots

Disable the indexing of the .snapshots directories by updatedb. It is enabled by default, which can cause significant slowdown and excessive memory usage if you have a large number of snapshots.

$ echo 'PRUNENAMES = ".snapshots"' | sudo tee -a /etc/updatedb.conf

Enable snapshot booting by appending the SUSE_BTRFS_SNAPSHOT_BOOTING="true" option to the /etc/default/grub file.

$ echo 'SUSE_BTRFS_SNAPSHOT_BOOTING="true"' | sudo tee -a /etc/default/grub

You must also make changes to the /boot/efi/EFI/fedora/grub.cfg file now that snapshot booting is enabled.

$ sudo sed -i '1i set btrfs_relative_path="yes"' /boot/efi/EFI/fedora/grub.cfg

Finally, update the grub.cfg file.

$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg

Later, I'll enable snapper timeline snapshots. For now, the snapper configuration is complete.

List the snapshots for / volume. For the root, you may use snapper -c root ls or simply snapper ls. Both provide the same output.

$ snapper ls
 # | Type   | Pre # | Date | User | Cleanup | Description | Userdata
---+--------+-------+------+------+---------+-------------+---------
0  | single |       |      | root |         | current     |

List the snapshots for /home subvolume.

$ snapper -c home ls
 # | Type   | Pre # | Date | User | Cleanup | Description | Userdata
---+--------+-------+------+------+---------+-------------+---------
0  | single |       |      | root |         | current     |

At this stage, you do not have any snapshots, we will create some later.

5. Install and Configure Grub-Btrfs

The grub-btrfs package adds 'Fedora Linux snapshots' to the GRUB menu and allows you to test a snapshot in read-only mode before rolling back to it in read-write mode.

Clone the grub-btrfs repository.

$ git clone https://github.com/Antynea/grub-btrfs

The setup is pre-configured to work with Arch and Gentoo out of the box. You must make a few changes to the grub-btrfs config file to make it work with Fedora.

$ cd grub-btrfs

$ sed -i '/#GRUB_BTRFS_SNAPSHOT_KERNEL/a GRUB_BTRFS_SNAPSHOT_KERNEL_PARAMETERS="systemd.volatile=state"' config
$ sed -i '/#GRUB_BTRFS_GRUB_DIRNAME/a GRUB_BTRFS_GRUB_DIRNAME="/boot/grub2"' config
$ sed -i '/#GRUB_BTRFS_MKCONFIG=/a GRUB_BTRFS_MKCONFIG=/sbin/grub2-mkconfig' config
$ sed -i '/#GRUB_BTRFS_SCRIPT_CHECK=/a GRUB_BTRFS_SCRIPT_CHECK=grub2-script-check' config

Then install it.

$ sudo make install

Update grub.cfg and enable the grub-btrfsd.service.

$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg
$ sudo systemctl enable --now grub-btrfsd.service

You will receive the 'No snapshots found' error since you have not yet created any snapshots, but don't worry, it will function properly after you do.

Your grub-btrfs installation is now complete. You may now delete the cloned grub-btrfs repository.

$ cd ..
$ rm -rvf grub-btrfs

6. Create a System Root Snapshot and Set It as the Default

Now that everything in Fedora has been installed and configured, it is time to take a subvolume snapshot of the main volume and set the subvolume as the default ‘/‘ file system. By manually creating a subvolume snapshot of the main volume and making it the default, you can easily rollback without having to specify the snapshot number and the 'ambit' during the rollback when using the snapper tool.

Create a directory named '1' in the /.snapshots directory.

$ sudo mkdir -v /.snapshots/1

Create an XML file called info.xml in the /.snapshots/1/ directory. Copy the following command from sudo to EOF, paste it into your terminal, and hit the <Enter> button.

$ sudo bash -c "cat > /.snapshots/1/info.xml" <<EOF
<?xml version="1.0"?>
<snapshot>
  <type>single</type>
  <num>1</num>
  <date>$(date -u +"%F %T")</date>
  <description>first root subvolume</description>
</snapshot>
EOF

Verify that the date is set properly and is in the Coordinated Universal Time (UTC) format.

$ cat /.snapshots/1/info.xml
<?xml version="1.0"?>
<snapshot>
  <type>single</type>
  <num>1</num>
  <date>2023-11-06 07:58:38</date>
  <description>first root subvolume</description>
</snapshot>

Now, create a read-write subvolume snapshot of the system root in the /.snapshots/1/ directory.

$ sudo btrfs subvolume snapshot / /.snapshots/1/snapshot

Get the subvolid of the /.snapshots/1/snapshot subvolume.

$ sudo btrfs inspect-internal rootid /.snapshots/1/snapshot
271

Using subvolid 271, set the /.snapshots/1/snapshot subvolume as the default subvolume for the root (/) filesystem.

$ sudo btrfs subvolume set-default 271 /

And reboot your system.

$ sudo reboot

After rebooting, confirm that the /.snapshots/1/snapshot subvolume is indeed the default for the / filesystem.

$ sudo btrfs subvolume get-default /
ID 271 gen 170 top level 269 path .snapshots/1/snapshot

Now check the snapshots in snapper.

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup | Description          | Userdata
---+--------+-------+-------------------------------------+------+---------+----------------------+---------
0  | single |       |                                     | root |         | current              |         
1* | single |       | Monday 06 November 2023 01:28:38 PM | root |         | first root subvolume |

As you can see, the /.snapshots/1/snapshot subvolume is also visible as snapshot #1 in snapper. The asterisk (*) indicates that this snapshot is the default and is currently active.

The installation of Fedora 39 with snapshot and rollback support is now complete. You can now begin taking snapshots.

7. Snapper Tests

I'll run some tests here to make sure everything is in working order and that there are no problems.

Test 1: Undo the Changes Made by the DNF Installer

In this test, I will use the dnf package manager to install a small package named ps_mem. I'll check the system after it is installed to see what changes were made. I'll then attempt to undo the changes and see if I can get the system back to its pre-installation state.

Install the ps_mem package. It displays the core memory used per program (not per process).

$ sudo dnf install ps_mem

Run the ps_mem program to see if it was installed successfully.

$ sudo ps_mem
 Private  +   Shared  =  RAM used	Program

144.0 KiB +  13.5 KiB = 157.5 KiB	fusermount3
196.0 KiB +  12.5 KiB = 208.5 KiB	inotifywait
292.0 KiB +  14.5 KiB = 306.5 KiB	mcelog
...
 48.2 MiB +   6.0 MiB =  54.2 MiB	gnome-software
190.6 MiB +   1.8 MiB = 192.4 MiB	packagekitd
234.3 MiB +  24.1 MiB = 258.4 MiB	gnome-shell
---------------------------------
                          1.1 GiB
=================================

Check the snapper for snapshots.

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup | Description                 | Userdata
---+--------+-------+-------------------------------------+------+---------+-----------------------------+---------
0  | single |       |                                     | root |         | current                     |         
1* | single |       | Monday 06 November 2023 01:28:38 PM | root |         | first root subvolume        |         
2  | pre    |       | Monday 06 November 2023 01:40:51 PM | root | number  | /usr/bin/dnf install ps_mem |         
3  | post   |     2 | Monday 06 November 2023 01:40:53 PM | root | number  | /usr/bin/dnf install ps_mem |

As you can see, the ps_mem package has pre (#2) and post (#3) snapshots.

Let's take a look at the changes it made to the system between snapshots #2 and #3.

$ snapper status 2..3
+..... /usr/bin/ps_mem
c..... /usr/lib/sysimage/rpm/rpmdb.sqlite-shm
c..... /usr/lib/sysimage/rpm/rpmdb.sqlite-wal
+..... /usr/share/doc/ps_mem
+..... /usr/share/doc/ps_mem/LICENSE
+..... /usr/share/man/man1/ps_mem.1.gz
c..... /var/lib/dnf/history.sqlite-shm
c..... /var/lib/dnf/history.sqlite-wal
-..... /var/lib/dnf/rpmdb_lock.pid

Now I'll undo the changes.

$ sudo snapper undochange 2..3
create:1 modify:4 delete:4

Check again to ensure that the ps_mem package was successfully uninstalled.

$ sudo ps_mem
sudo: ps_mem: command not found

Cool! The undo was successful. But, because I want to keep the package ps_mem, I'll undo the changes again. This time between snapshots #3 and #2.

$ sudo snapper undochange 3..2
create:4 modify:4 delete:1

Now run ps_mem again to see if it exists.

$ sudo ps_mem
 Private  +   Shared  =  RAM used	Program

144.0 KiB +  13.5 KiB = 157.5 KiB	fusermount3
196.0 KiB +  12.5 KiB = 208.5 KiB	inotifywait
292.0 KiB +  14.5 KiB = 306.5 KiB	mcelog
...
 48.2 MiB +   6.0 MiB =  54.2 MiB	gnome-software
190.6 MiB +   1.8 MiB = 192.4 MiB	packagekitd
234.3 MiB +  24.1 MiB = 258.4 MiB	gnome-shell
---------------------------------
                          1.1 GiB
=================================

Test 1 is successful.

Test 2: Undo Any Changes Made to Individual Files

Assume you're configuring something and editing a configuration file. Then you realize you messed up the configuration file. You want to see what changes you made to the original file and possibly wish you could undo the changes.

You can use snapper to undo not only all changes between two snapshots, but also a single file.

In this test, I will simply delete the last line of the /etc/hosts file. Then I'll compare it to the same file in snapshot #3 to see what changed and if I can undo all of the changes and restore it to its original state.

This is how the original /etc/hosts file looks.

$ cat /etc/hosts
# Loopback entries; do not change.
# For historical reasons, localhost precedes localhost.localdomain:
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
# See hosts(5) for proper format and other examples:
# 192.168.1.10 foo.mydomain.org foo
# 192.168.1.13 bar.mydomain.org bar

Now I'll remove the last line.

$ sudo sed -i '$d' /etc/hosts

$ cat /etc/hosts
# Loopback entries; do not change.
# For historical reasons, localhost precedes localhost.localdomain:
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
# See hosts(5) for proper format and other examples:
# 192.168.1.10 foo.mydomain.org foo

Now that I have removed the last line, using the snapper tool, compare the /etc/hosts file with the one in snapshot #3.

$ snapper diff 3..0 /etc/hosts
--- /.snapshots/3/snapshot/etc/hosts	2022-11-27 20:56:24.000000000 +0530
+++ /etc/hosts	2023-04-28 21:14:25.578325998 +0530
@@ -4,4 +4,3 @@
 ::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
 # See hosts(5) for proper format and other examples:
 # 192.168.1.10 foo.mydomain.org foo
-# 192.168.1.13 bar.mydomain.org bar

The number 0 in the command 3..0 represents the current snapshot, while the number 3 represents snapshot #3.

As you can see in the last line, the /etc/hosts file in the current snapshot is missing that line compared to the one in snapshot #3. If you want to learn how to read the output, take a look at the man pages man diff and man snapper.

To replace the /etc/hosts file with the one in snapshot #3, use the following command.

$ sudo snapper undochange 3..0 /etc/hosts
create:0 modify:1 delete:0

Check to see if the /etc/hosts file has indeed been rolled back.

$ cat /etc/hosts
# Loopback entries; do not change.
# For historical reasons, localhost precedes localhost.localdomain:
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
# See hosts(5) for proper format and other examples:
# 192.168.1.10 foo.mydomain.org foo
# 192.168.1.13 bar.mydomain.org bar

Test 2 is successful.

Test 3: Create Manual Pre-Post Snapshots and Undo the Changes

In my previous article, I performed a manual pre-post snapshots test for installing a package with Gnome Software. The concept for both tests is the same. If you want, you can also run that test.

In this test, I will begin by creating manual 'pre' snapshots of the / and /home directories. Then I'll install a small package called Color Picker (gcolor3) from GitHub by compiling it from the source file. When I'm finished, regardless of whether the compiling was successful or not, I'll create 'post' snapshots for the previously created 'pre' snapshots. I'll then look at the changes it made to the system between the pre-post snapshots and, finally, undo everything.

Create a manual 'pre' snapshot for both the / and /home directories.

$ snapper -c root create -t pre -c number -d 'Pre Color Picker'
$ snapper -c home create -t pre -c number -d 'Pre Color Picker'

List the snapshots.

$ snapper ls
 # | Type   | Pre # | Date                                | User  | Cleanup | Description                 | Userdata
---+--------+-------+-------------------------------------+-------+---------+-----------------------------+---------
0  | single |       |                                     | root  |         | current                     |         
1* | single |       | Monday 06 November 2023 01:28:38 PM | root  |         | first root subvolume        |         
2  | pre    |       | Monday 06 November 2023 01:40:51 PM | root  | number  | /usr/bin/dnf install ps_mem |         
3  | post   |     2 | Monday 06 November 2023 01:40:53 PM | root  | number  | /usr/bin/dnf install ps_mem |         
4  | pre    |       | Monday 06 November 2023 02:02:54 PM | madhu | number  | Pre Color Picker            |

$ snapper -c home ls
 # | Type   | Pre # | Date                                | User  | Cleanup | Description      | Userdata
---+--------+-------+-------------------------------------+-------+---------+------------------+---------
0  | single |       |                                     | root  |         | current          |         
1  | pre    |       | Monday 06 November 2023 02:03:02 PM | madhu | number  | Pre Color Picker |

Install the pre-requisite packages before compiling the source file.

$ sudo dnf install meson gcc-c++ libhandy-devel libportal-devel \
    libportal-gtk3-devel

Compile the source.

$ git clone https://github.com/Hjdskes/gcolor3.git
$ cd gcolor3
$ meson setup build
$ ninja-build -C build
$ sudo ninja-build -C build install

Make sure the Color Picker package has been installed properly. Enter gcolor3 into the terminal and hit <Enter>. The Color Picker app must be open and appear as shown.

Install Fedora with Snapshot and Rollback Support - Gcolor3

Now that you have successfully installed the Color Picker application, close the application and create 'post' snapshots for the / and /home directories.

$ snapper -c home create -t post --pre-number 1 -c number -d 'Post Color Picker'
$ snapper -c root create -t post --pre-number 4 -c number -d 'Post Color Picker'

List the snapshots.

$ snapper -c root ls
 # | Type   | Pre # | Date                                | User  | Cleanup | Description                                                                            | Userdata
---+--------+-------+-------------------------------------+-------+---------+----------------------------------------------------------------------------------------+---------
0  | single |       |                                     | root  |         | current                                                                                |         
1* | single |       | Monday 06 November 2023 01:28:38 PM | root  |         | first root subvolume                                                                   |         
2  | pre    |       | Monday 06 November 2023 01:40:51 PM | root  | number  | /usr/bin/dnf install ps_mem                                                            |         
3  | post   |     2 | Monday 06 November 2023 01:40:53 PM | root  | number  | /usr/bin/dnf install ps_mem                                                            |         
4  | pre    |       | Monday 06 November 2023 02:02:54 PM | madhu | number  | Pre Color Picker                                                                       |         
5  | pre    |       | Monday 06 November 2023 02:05:52 PM | root  | number  | /usr/bin/dnf install meson gcc-c++ libhandy-devel libportal-devel libportal-gtk3-devel |         
6  | post   |     5 | Monday 06 November 2023 02:06:21 PM | root  | number  | /usr/bin/dnf install meson gcc-c++ libhandy-devel libportal-devel libportal-gtk3-devel |         
7  | post   |     4 | Monday 06 November 2023 02:08:23 PM | madhu | number  | Post Color Picker                                                                      |

$ snapper -c home ls
 # | Type   | Pre # | Date                                | User  | Cleanup | Description       | Userdata
---+--------+-------+-------------------------------------+-------+---------+-------------------+---------
0  | single |       |                                     | root  |         | current           |         
1  | pre    |       | Monday 06 November 2023 02:03:02 PM | madhu | number  | Pre Color Picker  |         
2  | post   |     1 | Monday 06 November 2023 02:08:11 PM | madhu | number  | Post Color Picker |

Review the changes made to the system between the pre and post snapshots.

$ snapper -c home status 1..2
+..... /home/madhu/.config/gcolor3
+..... /home/madhu/.config/gcolor3/config.ini
+..... /home/madhu/gcolor3
+..... /home/madhu/gcolor3/build
+..... /home/madhu/gcolor3/build/build.ninja
...
+..... /home/madhu/.local/share/gnome-shell/application_state
c..... /home/madhu/.local/share/gvfs-metadata/root
-..... /home/madhu/.local/share/gvfs-metadata/root-3616f454.log
+..... /home/madhu/.local/share/gvfs-metadata/root-54385136.log

$ snapper -c root status 4..7
c..... /boot/grub2/grub-btrfs.cfg
c..... /boot/grub2/grub.cfg
+..... /etc/alternatives/ld
c..... /etc/ld.so.cache
+..... /usr/bin/addr2line
...
+..... /usr/share/xml/dbus-1/catalog.xml
+..... /usr/share/xml/dbus-1/introspect.dtd
+..... /usr/share/zsh/site-functions/_meson
+..... /usr/share/zsh/site-functions/_ninja
+..... /var/lib/alternatives/ld
c..... /var/lib/dnf/history.sqlite
c..... /var/lib/dnf/history.sqlite-shm
c..... /var/lib/dnf/history.sqlite-wal

This is the total number of files added, removed, or modified.

$ snapper -c home status 1..2 | wc -l
278

$ snapper -c root status 4..7 | wc -l
13913

I'll now undo the changes in the / and /home directories.

$ sudo snapper -c home undochange 1..2
create:1 modify:3 delete:274

$ sudo snapper -c root undochange 4..7
create:0 modify:13 delete:13900

The Color Picker package will be completely removed from the system.

Log out and then log back in.

$ gnome-session-quit

Check again to see if the Color Picker has been completely removed.

$ gcolor3
bash: gcolor3: command not found...

Since you removed the Color Picker package, there is no reason to keep its pre-post snapshots if you do not intend to use it again. So you can delete those snapshots.

$ snapper -c home delete 1-2
$ snapper -c root delete 4-7

Test 3 is successful.

Test 4: Rollback to a Previous Snapshot from the GRUB Menu

In this rollback test, I will delete the most critical files and directories on which the Linux operating system relies. These include Linux kernel and initramfs files in the /boot directory, the /etc directory, which contains all configuration files, and the /usr directory, which contains all drivers, kernel modules, and library files.

Once I delete these files and directories, I will be unable to issue any commands because the Linux OS is pretty much dead, and the system will undoubtedly fail the next time it boots. So I'll hard boot the system and see if I can save the day by rolling back to a working snapshot.

So, before I delete them, here's how they appear.

$ sudo du -sch /boot /etc /usr
254M	/boot
33M	/etc
5.9G	/usr
6.1G	total

Now delete the files and directories.

$ sudo rm -rvf /boot/{vmlinuz,initramfs}* /etc /usr

Boom!!! All critical files have been removed. Your Linux system is no longer operational. Reboot the system. Your system should now fail to boot and display something like this.

Install Fedora with Snapshot and Rollback Support - Boot Error

Return to the GRUB menu and this time boot from snapshot #3.

Install Fedora with Snapshot and Rollback Support - Snapshots Menu
Install Fedora with Snapshot and Rollback Support - Select Snapshot #3
Install Fedora with Snapshot and Rollback Support - Select Latest Kernel

Open the terminal and make sure everything is back to normal.

$ sudo ls /boot /etc /usr

Because you booted into the snapshot, the '/' file system is read-only.

$ sudo btrfs property get -ts /
ro=true

Now that everything appears to be operating properly, it is time to roll back this snapshot in read-write mode.

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup | Description                 | Userdata
---+--------+-------+-------------------------------------+------+---------+-----------------------------+---------
0  | single |       |                                     | root |         | current                     |         
1+ | single |       | Monday 06 November 2023 01:28:38 PM | root |         | first root subvolume        |         
2  | pre    |       | Monday 06 November 2023 01:40:51 PM | root | number  | /usr/bin/dnf install ps_mem |         
3- | post   |     2 | Monday 06 November 2023 01:40:53 PM | root | number  | /usr/bin/dnf install ps_mem |

As you can see from the output, snapshot #1 has a '+' symbol, indicating that it is the default subvolume, whereas snapshot #3 has a '-' symbol, indicating that it is the currently booted subvolume.

$ sudo snapper rollback
Ambit is classic.
Creating read-only snapshot of default subvolume. (Snapshot 4.)
Creating read-write snapshot of current subvolume. (Snapshot 5.)
Setting default subvolume to snapshot 5.

Now, reboot your system.

$ sudo reboot

The first thing you should do after a rollback is to update the grub.cfg file so that the GRUB menu snapshots are always in sync.

$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg

Check the system once again.

$ sudo du -sch /boot /etc /usr
254M	/boot
33M	/etc
5.9G	/usr
6.1G	total

$ sudo btrfs property get -ts /
ro=false

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup | Description                 | Userdata     
---+--------+-------+-------------------------------------+------+---------+-----------------------------+--------------
0  | single |       |                                     | root |         | current                     |              
1  | single |       | Monday 06 November 2023 01:28:38 PM | root | number  | first root subvolume        |              
2  | pre    |       | Monday 06 November 2023 01:40:51 PM | root | number  | /usr/bin/dnf install ps_mem |              
3  | post   |     2 | Monday 06 November 2023 01:40:53 PM | root | number  | /usr/bin/dnf install ps_mem |              
4  | single |       | Monday 06 November 2023 03:42:54 PM | root | number  | rollback backup of #1       | important=yes
5* | single |       | Monday 06 November 2023 03:42:54 PM | root |         | writable copy of #3         |

$ sudo btrfs subvolume list /
ID 256 gen 281 top level 5 path home
ID 257 gen 162 top level 5 path var/lib/machines
ID 258 gen 96  top level 5 path opt
ID 259 gen 278 top level 5 path var/cache
ID 260 gen 97  top level 5 path var/crash
ID 261 gen 283 top level 5 path var/log
ID 262 gen 277 top level 5 path var/spool
ID 263 gen 281 top level 5 path var/tmp
ID 264 gen 99  top level 5 path var/www
ID 265 gen 277 top level 5 path var/lib/AccountsService
ID 266 gen 278 top level 5 path var/lib/gdm
ID 267 gen 101 top level 5 path var/lib/libvirt/images
ID 268 gen 117 top level 256 path home/madhu/.mozilla
ID 269 gen 283 top level 5 path .snapshots
ID 270 gen 262 top level 256 path home/.snapshots
ID 271 gen 272 top level 269 path .snapshots/1/snapshot
ID 272 gen 193 top level 269 path .snapshots/2/snapshot
ID 273 gen 273 top level 269 path .snapshots/3/snapshot
ID 274 gen 272 top level 269 path .snapshots/4/snapshot
ID 275 gen 281 top level 269 path .snapshots/5/snapshot

$ sudo btrfs subvolume get-default /
ID 275 gen 281 top level 269 path .snapshots/5/snapshot

You successfully restored the system with the latest working snapshot in read and write mode.

Test 4 is successful.

8. Make a Snapshot the New System Root

Now that you've tested the snapper undo and rollback features and are hopefully satisfied with the results, you might want to set one of the snapshots as the new default system root and resume normal operating system use.

But first, let me show you how to determine how much space each snapshot takes up on your disk.

$ sudo btrfs filesystem du -s --human-readable /.snapshots/*/snapshot
     Total   Exclusive  Set shared  Filename
  55.34MiB       0.00B    55.34MiB  /.snapshots/1/snapshot
   5.90GiB    32.00KiB     5.84GiB  /.snapshots/2/snapshot
   5.90GiB    52.00KiB     5.84GiB  /.snapshots/3/snapshot
  55.34MiB       0.00B    55.34MiB  /.snapshots/4/snapshot
   5.90GiB   244.00KiB     5.84GiB  /.snapshots/5/snapshot

As you can see from the output above, snapshot #1 has an exclusive size of 0 bytes. This is because, as you may recall, I deleted all of the files recursively. Snapshot #4 is also 0 bytes in size because it is a read-only duplicate of snapshot #1.

To find out how the 'Total' and 'Set shared' values are calculated, see the man page man btrfs-filesystem.

Now, let's return to making a snapshot the new system root.

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup | Description                 | Userdata     
---+--------+-------+-------------------------------------+------+---------+-----------------------------+--------------
0  | single |       |                                     | root |         | current                     |              
1  | single |       | Monday 06 November 2023 01:28:38 PM | root | number  | first root subvolume        |              
2  | pre    |       | Monday 06 November 2023 01:40:51 PM | root | number  | /usr/bin/dnf install ps_mem |              
3  | post   |     2 | Monday 06 November 2023 01:40:53 PM | root | number  | /usr/bin/dnf install ps_mem |              
4  | single |       | Monday 06 November 2023 03:42:54 PM | root | number  | rollback backup of #1       | important=yes
5* | single |       | Monday 06 November 2023 03:42:54 PM | root |         | writable copy of #3         |

The output indicates that snapshot #5 is the default subvolume, and since it is operational, you can simply delete the remaining snapshots and move on.

However, I will use snapshot #2 as the default because it is a 'pre' snapshot that was created just before ps_mem was installed and is clean.

So, first, delete all of the snapshots except #2. You cannot delete snapshot #5 because it is the active one.

$ snapper delete 1
$ snapper delete 3-4

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup | Description                 | Userdata
---+--------+-------+-------------------------------------+------+---------+-----------------------------+---------
0  | single |       |                                     | root |         | current                     |         
2  | pre    |       | Monday 06 November 2023 01:40:51 PM | root | number  | /usr/bin/dnf install ps_mem |         
5* | single |       | Monday 06 November 2023 03:42:54 PM | root |         | writable copy of #3         |

Create a directory named '1' in the /.snapshots directory.

$ sudo mkdir -v /.snapshots/1

Copy the info.xml file from /.snapshots/2/ to /.snapshots/1/.

$ sudo cp -v /.snapshots/2/info.xml /.snapshots/1/

Edit the /.snapshots/1/info.xml file and change the content from this...

$ sudo cat /.snapshots/1/info.xml
<?xml version="1.0"?>
<snapshot>
  <type>pre</type>
  <num>2</num>
  <date>2023-11-06 08:10:51</date>
  <description>/usr/bin/dnf install ps_mem</description>
  <cleanup>number</cleanup>
</snapshot>

...to this. Changes are in amber.

$ sudo cat /.snapshots/1/info.xml
<?xml version="1.0"?>
<snapshot>
  <type>single</type>
  <num>1</num>
  <date>2023-11-06 08:10:51</date>
  <description>new root subvolume</description>
</snapshot>

Create a read-write subvolume snapshot of snapshot #2 in the /.snapshots/1/ directory.

$ sudo btrfs subvolume snapshot /.snapshots/2/snapshot /.snapshots/1/snapshot

Get the subvolid of the /.snapshots/1/snapshot subvolume.

$ sudo btrfs inspect-internal rootid /.snapshots/1/snapshot
276

Using subvolid 276, set the /.snapshots/1/snapshot subvolume as the default subvolume for the root (/) filesystem.

$ sudo btrfs subvolume set-default 276 /

Then reboot.

$ sudo reboot

After rebooting, confirm that the /.snapshots/1/snapshot subvolume is indeed the default for the / filesystem.

$ sudo btrfs subvolume get-default /
ID 276 gen 418 top level 269 path .snapshots/1/snapshot

And is writable.

$ sudo btrfs property get -ts /
ro=false

Take a look at the snapper now.

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup | Description                 | Userdata
---+--------+-------+-------------------------------------+------+---------+-----------------------------+---------
0  | single |       |                                     | root |         | current                     |         
1* | single |       | Monday 06 November 2023 01:40:51 PM | root |         | new root subvolume          |         
2  | pre    |       | Monday 06 November 2023 01:40:51 PM | root | number  | /usr/bin/dnf install ps_mem |         
5  | single |       | Monday 06 November 2023 03:42:54 PM | root |         | writable copy of #3         |

As you can see, snapshot #1 is the default. You can now delete the remaining snapshots.

$ snapper delete 2-5

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup | Description        | Userdata
---+--------+-------+-------------------------------------+------+---------+--------------------+---------
0  | single |       |                                     | root |         | current            |         
1* | single |       | Monday 06 November 2023 01:40:51 PM | root |         | new root subvolume |         

$ sudo btrfs filesystem du -s --human-readable /.snapshots/*/snapshot
     Total   Exclusive  Set shared  Filename
   5.90GiB   268.00KiB     5.84GiB  /.snapshots/1/snapshot

You're done.

9. Enable Automatic Timeline Snapshots

Now that you've finished everything, you can enable automatic timeline snapshots. When the timeline is enabled, a snapshot is created once every hour. Once per day, the timeline cleanup algorithm cleans up the snapshots.

It is enabled by default in both the root and home configurations. Enable it only for the system root and disable it for the home. See the Arch Wiki page on 'Automatic timeline snapshots' for more information.

$ sudo snapper -c home set-config TIMELINE_CREATE=no
$ sudo systemctl enable --now snapper-timeline.timer
$ sudo systemctl enable --now snapper-cleanup.timer

That's all. Every hour from now on, a 'single' snapshot will be created and cleaned up every other day.

$ snapper ls
 # | Type   | Pre # | Date                                | User | Cleanup  | Description        | Userdata
---+--------+-------+-------------------------------------+------+----------+--------------------+---------
0  | single |       |                                     | root |          | current            |         
1* | single |       | Monday 06 November 2023 01:40:51 PM | root |          | new root subvolume |
2  | single |       | Monday 06 November 2023 02:00:01 PM | root | timeline | timeline           |

To stop timeline snapshots, disable the snapper timers.

$ sudo systemctl disable --now snapper-timeline.timer
$ sudo systemctl disable --now snapper-cleanup.timer

The installation of Fedora 39 with snapshot and rollback support is now complete.

10. Issues and Possible Solutions

Problem 1: Sometimes, after updating Fedora and rebooting, you may encounter a boot error like this:

error: ../../grub-core/script/lexer.c:352:syntax error.
error: ../../grub-core/script/lexer.c:352:Incorrect command.

Issue: This usually occurs when a kernel update has just been released and all of the kernel's supporting files have not yet been propagated to a repository mirror near you.

This is caused by the kernel parameter '{extra_cmdline}'. The '{extra_cmdline}' parameter is added to the kernel when you add the 'SUSE_BTRFS_SNAPSHOT_BOOTING=true' key to the /etc/default/grub file.

Solution: From the GRUB menu, select the kernel version you want to boot, and then press 'e' to modify the command.

Go to the line that starts with the word 'linux', and move the parameter '{extra_cmdline}' to the end of the line. The parameter '{extra_cmdline}' should always be at the end of the line.

From this:

Install Fedora with Snapshot and Rollback Support - Issue 1

To this:

Install Fedora with Snapshot and Rollback Support - Solution 1

Then, on your keyboard, press Ctrl+x. You will be successfully booted into the operating system. Next, launch the terminal and execute the following command.

$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg

Reboot the computer to ensure the problem has been resolved.

11. Upgrade Fedora 38 to Fedora 39

If you've already followed an earlier version of this tutorial and installed Fedora 38 and want to upgrade to Fedora 39, this section is for you.

Update the local DNF metadata cache.

$ sudo dnf makecache

Update your Fedora 38 release. This is important. Do not skip this step.

$ sudo dnf upgrade --refresh

After the updates have been installed, reboot your computer.

$ sudo reboot

After rebooting, open the terminal and run the following command to upgrade your Fedora 38 operating system to the most recent Fedora 39 version.

$ sudo dnf system-upgrade download --releasever=39

Once the upgrades have been downloaded, trigger the upgrade process. This will immediately reboot your computer, with no countdown or confirmation. So, before issuing the following command, close all other programs and save your work.

$ sudo dnf system-upgrade reboot

Once the upgrade process completes, your system will reboot again into the updated release version of Fedora 39.

If you want to learn more about the upgrade process, check out this link.

12. Watch on YouTube

The video was made for Fedora 38, but it is also applicable to Fedora 39. Nothing has changed between Fedora 38 and Fedora 39 in terms of btrfs snapshot and rollback support.

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