Mounting Archives

Borg UI can call borg mount so an archive appears as a read-only filesystem inside the container.

Use archive mounting when you need filesystem access to archive contents. For normal file restore, the Archives page is usually simpler.

Requirements

Archive mounting requires FUSE support from the Docker host.

The same Docker FUSE access is also needed for SSHFS-based remote source backups and SSH restore destinations.

Add this to the Borg UI service:

cap_add:
  - SYS_ADMIN
devices:
  - /dev/fuse:/dev/fuse
security_opt:
  - apparmor:unconfined
environment:
  - BORG_FUSE_IMPL=pyfuse3

Mount an Archive

1. Open Archives.
2. Select a repository and archive.
3. Choose Mount.
4. Pick a mount name.

Mounted archives appear under:

/data/mounts/<mount-name>

Mounts are read-only.

Inspect from the Container

docker exec -it borg-web-ui ls /data/mounts
docker exec -it borg-web-ui ls /data/mounts/my-backup

Replace borg-web-ui with your container name if you changed it.

Make Mounts Visible on the Host

If you need host access to mounted archives, bind /data/mounts with shared propagation:

volumes:
  - type: bind
    source: /mnt/borg-ui-mounts
    target: /data/mounts
    bind:
      propagation: shared

Your Docker host and filesystem must support shared mount propagation.

Unmount

Use Settings > Management > Mounts to unmount.

Force unmount is available when a mount is busy. Use it only after closing processes that may be reading from the mount.

Mounts do not survive container restarts.

Troubleshooting

Operation not permitted

FUSE is not available to the container. Check /dev/fuse, SYS_ADMIN, and AppArmor settings.

fusermount3: mount failed: Permission denied

On Ubuntu 25.04 and newer, the host's own AppArmor profile for fusermount3 restricts where FUSE filesystems may be mounted, and the container's apparmor:unconfined does not lift it. Confirm with apparmor="DENIED" ... info="failed mntpnt match" in dmesg, and see Optional FUSE Access for the host-side drop-in.

Mount is busy

Close shells, file browsers, or processes using the mounted path, then unmount again.

Mount takes too long

Increase the mount timeout in Settings > System > Operation Timeouts.