What is your go-to backup system for Linux servers?

Currently I would recommend Restic <https://restic.net/>, which I use it both for personal and professional backups. It can have some rough edges, but all-in-all it's the "best" (as in a good balance between ease of use, complexity and sustainability) for my own use-case.

In the past I've used `rdiff-backup` due to the lack of a better suited (to my use-case) alternative.

Please note the emphasis on "my use-case"! Thus, a good backup solution must make sense for your own context. Choosing the most "popular" solution might not be a good option if it's too complex (or expensive) for you to use, or the worst case scenario to recover data from.

Perhaps start small: even a copy (i.e. `rsync`) of your data on an external hard-drive is good enough than nothing at all, or if using OSX then try TimeMachine first. Then gradually move to better suited solutions.

ZFS send to a TrueNAS server if you can have it, otherwise Restic to anywhere.

Another vote here for restic along with hot rsyncs as needed to a TrueNas

I have been using duplicity so far and it does the job

Kopia is nice (kopia.io)