Yes, this works great. On macOS, external drives usually mount under /Volumes/NameOfDrive. You just need to map this path into the Docker container in your docker-compose.yml.
Example: - /Volumes/MyBackupDrive:/mnt/backup_drive
Ensure that you grant Docker Desktop permission to access “Removable Volumes” in your Mac’s System Settings -> Privacy & Security -> Files and Folders (or “Full Disk Access”), otherwise the container might not see the external drive.”
File System Requirements (Crucial for Mac): Because BmuS uses Hardlinks for deduplication (to save massive amounts of space), the file system matters:
- Recommended: APFS (Apple File System) or Mac OS Extended (HFS+). These are the native Mac formats. They support hardlinks perfectly. Since Docker maps the drive from macOS to the Linux container, BmuS can utilize the Mac’s native file system features to create space-saving backups.
- Not Recommended: exFAT or FAT32. Many external drives come pre-formatted as exFAT. Do not use this for BmuS. exFAT does not support hardlinks. BmuS would still work, but it would have to create a full copy every single time instead of just saving the changes. Your drive would fill up very quickly.