I use restic.

Borg has worked well for me. Also supports compression, encryption and deduplication.

Restic is my go-to.

FreeFileSync is FOSS and works pretty well for me. It can be set up for automated sync on a schedule or you can just manually sync files between two destinations. I haven't really tinkered with the automated stuff but if what you want is to open up a program and hit a button to sync, it can definitely do that.

The question really is what data you‘re trying to back up.

Would you be annoyed, sad, very sad or potentially ruined if that data goes away?

Depending on your threat level, you should choose one that strikes the balance between cost and reliability.

If you don’t have tons of data and it’s not insanely important data, use something free to encrypt/stripe it over free google/dropbox/onedrive accounts.

If it is insanely important data, you can try tarsnap. I just heard of it but stripe uses it for their credit card data.

I personally use idrive. Has worked well so far but is paid as well and I didnt have to restore yet.

Good luck.

Hey, I'd recommend taking a look at Syncthing. It's software that runs locally, and you can configure the synchronisation to occur in a unidirectional flow instead of bidirectional. I.e. configure it to only synchronise data from the source drive to the backup drive.

Hope this helps and all the best!

EDIT: As pointed out, Syncthing is more suited to syncing data between two or more devices so may not be the right solution for OPs use case.

I'm using good old rsync in a command line

Kopia

rclone with backblaze b2.Goodl luck finding a cheaper solution that's actually durable.

Bvckup (not a typo)

Made by a little Swiss company, extremely light but very competent. Stays completely out of your way unless it absolutely must get your attention (which is usually never).

I think it's paid only but it's very reasonable. Works great in intermittent situations, I. E. It won't blow up if it tries to run a scheduled backup and the source or target is disconnected etc... Works very well for me for a decade.

I recently set up rsnapshot. You set the backup cadence as a cron job. And then every time it runs, it hard links all the files that haven't changed, then rsyncs all the files that have changed. So you could go back to three days ago if you set it up that way. Or last month. Or whatever works for your use case.

The catch is that it has to pull the files rather than push, so if you have a Synology or something with a smaller OS, it may not support rsnapshot. For my Synology, I had to create a docker container for it to work, since there was no way to install it directly on the host OS.

I have a similar setup (external USB drive that I periodically plugin to backup stuff), and I use rsnapshot which is based on the venerable rsync utility. It is a command line solution that I've used for many years and it allows you to do daily, weekly, or even monthly backups.

I also use rsnapshot for handling remote backups as well, so it is pretty versatile.

I am very happy using duply, that uses duplicity. Works well both for mounted disks or S3.

I would ignore any recommendations of a sync tool like Dropbox. They will very happy propagate your problem in all your places before you realized it.

Adding to what has already been said by other commenters, if the data is really important you should consider an off-site backup in addition to your external hard drive backup. It could be Dropbox, Google Drive, Backblaze, a hard drive in another place, as long as you can recover your data in case your home gets robbed or destroyed (flood, fire).

I'm also interested in this, I use Syncthing for multi-device sync, but it's not aimed for multi-directoy in a single device backup

Am I the only one here who uses backintime? It is easy to use and supports incremental backups.

Am I the only one out here using Clonezilla? Am I that out of touch?

No it's the children who are wrong.

Lot's of recommendations here thank you everyone. Will take me a little bit of time to read through all the options here but there looks to be same great solutions.

Thank you very much.