Copy/paste works fine for "data", but not so much for many other items you probably want to backup too. Maintaining file permissions, ownership, groups and any special settings usually needs more. That is why using a real backup program is important.
Originally Posted by TWFJR
So a very simplistic backup would be a 100G / that would be backed up to a 200G external USB drive. When connected the USB drive gets mounted as /media/Backups. Both are formated as EXT4 (or any UNIX file system) including the backup media location. The 200G will allow 3+ months of backups to be retained. In my world, 120% gets me 60 days of backups, but YMMV.
The command would be
Run that same command over daily and incremental backups will be very quick. Only the 1st one will take time. Easy-peasy.
sudo rdiff-backup --exclude-special-files --exclude=/media / /media/Backups
After the first 30-120 days, you'll probably want to remove older backups to manage space. There's an rdiff-backup command for that too. I hope this makes sense and is something easily followed. The most recent backup looks like a mirror under /media/Backups/ , so restoring 1 file is trivial.
Anyway, I hope this helps. Sorry that I don't know much about duplicity. I had hoped that someone else would have responded by now.