So I installed raspian (ugh) on rpi4, attached 2tb external hdd, formatted it to btrfs installed samba, and I'm doing backups. Works well so far, 71mb from 2gb of ram used, small load (~0.13).
@kuba
Borg backup for my Linux boxes. I'll try to us Kopia for wife's Windows machine (it's hard to find decent backup software for windows)
@TeddyDD I used Duplicati on Windows and wasn't disappointed
@TeddyDD what software are you using for backups?