Butterfly-Backup VS linux-timemachine

> I am concerned about the longevity of my archives

If you're concerned about archival longevity, and I for one certainly are, then maybe consider not to compress at all. Both compression and encryption add to obscurity and loss of redundancy in the backup. Using a widely understood file system and a very obvious arrangement of the data (for me that means: directories with dates, below a tree of files that mimics their original locations) will be a huge plus should the data have to be recovered at some point in the future.

Personally I am using a slightly adapted version of https://github.com/cytopia/linux-timemachine for this task. You do get de-duplication for the file transfer, but each file is written as it was on the target. You'll get a timestamped directory for each time a backup was run. Like MacOS' timemachine, the script uses hard links to de-duplicate identical files across different timestamped directories so the overall space requirement for that incremental backup you did an hour or a day later can be very small.

I can certify that this setup, while it does not occupy the least conceivable amount of storage area, is very amenable to be searched and trivial to use for recovery. much better in this regard than any kind of compressed archive format which are always a pain in terms of searchability and so on.

And for file version history and to protect against accidental deletion i use linux-timemachine which backs up over SSH to the same server and keeps versioned incremental backups. This backup also includes my entire /home folder so all apps, appdata and config is contained here.

Linux-TimeMachine: https://github.com/cytopia/linux-timemachine

If you only want to backup specific folders i like the tool linux-timemachine which uses rsync and hardlinks to create incremental backups based on a input and output folder.

You know, another option might be to just rely on something external to your machine if you're worried enough. When I'm dealing with personal machines (usually servers) that are important to me, I usually use Backblaze B2. You could maybe even try using open source variants of Time Machine designed for Linux machines or Borg Backup...though, to be fair, I've never really tried using them for backing up my entire system ( "/" ) partition (https://github.com/cytopia/linux-timemachine).

linux-timemachine