What is the difference between “Flat Structure” and “Date Folders” mode?

Q: What is the difference between “Flat Structure” and “Date Folders” mode? 
A: BmuS automatically detects your backup style.

  • Date Folders: If you enable BACKUP_USE_DATE_FOLDERS=1 or DEDUP_ENABLE=1, BmuS creates a new folder for every backup (e.g., 2025-11-28). Retention deletes the entire folder when it gets too old.
  • Flat Structure: If disabled, files are copied directly into the backup root. BmuS will delete individual files based on their age (mtime) to save space.