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Auto-Mounting Secondary Drives

Preliminary Warnings​

This is an edited version of the Bazzite documentation.

You may lose data on the drive(s) or result in an unbootable system if configured improperly.

Follow this guide at your own discretion and make sure to read the entire document relevant to your method, so you do not miss anything!

Formatting a disk​

This will wipe all existing data on it

Note when formatting in KDE Partition Manager​

Make sure you set permissions to everyone.

Use a disk graphical user interface like KDE Plasma or GNOME Disks to format your drive. We recommend formatting secondary drives to BTRFS or Ext4. BTRFS is our recommended filesystem, but Ext4 may be better for older spinning mechanical HDDs as secondary drives.

Creating a secondary drive directory and where to mount drives?​

/var/mnt should NOT be the path, but create a new directory in either /var/mnt or /var/run/media/.

  • /var/mnt/... for permanent drives
  • /var/run/media/... for removable drives

Drive directories should be lowercase with no spaces for best practice.

You can make a directory in /var/mnt/ by opening a host terminal and entering this command in a host terminal:

sudo mkdir /var/mnt/data

The drive will now be mounted in a directory known as data.

Permissions for the drive​

sudo chown $USER:$USER /var/mnt/data

If you plan to reformat the partition, remember to edit the mount point and "Remove" the mount path before you reformat! If not you will have to manually edit /etc/fstab.

Graphical User Interface (GUI) Methods for Auto-Mounting​

Do not set up auto-mount, unmount then format a drive! It can confuse the software you are configuring drives with. Instead, remove the auto-mount first before formatting the drive.

Instructions​

  1. Open KDE Partition Manager

  2. Locate the disk and partition you want to mount

  3. Right click on the partition and click "Edit Mount Point"

  4. Select "Identify by: UUID" (This will guarantee you mount THIS partition instead of a different one if the device nodes change for some reason)

  5. Select a mounting path (You would want to use /var/mnt/data or something similar for permanent mounts)

  6. Untick all the boxes in the graphical application if they are checked

  7. Click "More..." and add extra options depending on what filesystem is on the partition (read the "Filesystem Arguments" section)

  8. Click OK on both windows to save the mount points.

  9. A message will appear that the actions will edit /etc/fstab (Click "OK" to continue)

  10. Mount the disk manually in KDE Partition Manager and enter your sudo password

  11. Open the terminal to test the mounts by running the command:

    sudo systemctl daemon-reload && sudo mount -a

  12. If no errors appeared then it should be safe to reboot.

If an error occurs, then research the error and undo what you did and try again.

Also a Display Name should be added to the drive too. Name it whatever you want it to be identified as.

Required additional options depending on filesystem​

Use the below generic options depending on your filesystem (these are just good defaults) You can copy+paste these into the "More.." dialog and they will be valid "Users can mount and unmount" is an optional setting.

Filesystem arguments​

If a drive is formatted, then do not remove it from /etc/fstab, so the "nofail" option is a must to avoid issues with booting.

BTRFS:​

defaults,compress-force=zstd:3,noatime,lazytime,commit=120,space_cache=v2,nofail

Ext4:​

defaults,noatime,errors=remount-ro,nofail,rw,users,exec

NTFS:​

defaults,noatime,nofail,rw,users,exec

Advanced Options (Not required for most setups)​

Change at your own risk!

Information about compression:​

3 is a good balance, older CPUs should use 1.

Information about subvolumes:​

use subvol=name as an option, KDE and GNOME Disks let you only mount 1 subvolume through the GUI, you can mount the root with subvol=/ if a default subvolume is configured in the filesystem.

Alternative Methods to Auto-Mount Secondary Drives​

There are also two command-line interface (CLI) methods.

  1. Using systemd.mount

  2. Editing the /etc/fstab file