Free and Open Source Software

Just a reminder. Consider and test your restore process as well. Backups without restore testing are kind of questionable. Also think how the restore will go. Do you want to do a bare metal restore, or will you just reinstall, and restore certain things for example. Lot of these backup methods will not get a true bare metal restore set, nor can file system backups be "perfect" if they are done on a running system. Databases and things like cryptfs mounts for example can be problematic for example. Nor do all tools necessarily backup the full structure of the file system.

Not saying these are always issues, just be aware of them.

I work with VMs mostly, so I go for Veeam B&R. The free tier allows you to backup 10 VMs or machines.

I'm currently working on a disaster recovery plan using fsarchiver. I have very limited experience with it so far, but it had the features and social proof I was looking for.

I have so far used it to create offline filesystem backups of two volumes, one was LUKS encrypted (has to be manually "opened" with cryptsetup).

It can backup live filesystems which was important to me.

It's early days for my experience with this, but I'm sure others have used it and might chime in.

I like pikabackup it’s based on borg

I'm currently using TimeShift to backup my desktop onto an external hard drive (the why is because of how simple it is to use) and I'll be making a copy of anything I upload to my jellyfin server onto the external hard drive as well. I hope to eventually have a dedicated backup server and have a duplicate of it at a friend's house for offside backup too

I've used borg for a while and like it a lot. I would say your best option for pure linux is borg+borgmatic/vorta just because borg is battle-tested.

If you run any other OSs and don't mind a relative newcomer, I've found kopia to be easy to recommend to my windows friends. At this point kopia has been around long enough (~4 years of actual beta) that I think it's safe to trust its integrity with personal data. It has all the important features from borg in a cross-platform solution, so it's also a viable alternative for borg on linux if you don't like borg's frontends for whatever reason.

I've used Borg for years now. It's been rock solid. I test my backups regularly and have done several actual recoveries. I trust it with my data, which is the best thing I can say about backup software.