Disaster Recovery Backups With Rsync

When I started out, my main backup was a simple external drive that copied some data from my mounted NAS share. Then, when I revamped my NAS, I switched to using another external drive, but using ZFS replication (manually) . I didn't quite like that I was no longer updating my old LUKS backup drive, so I set out to rethink how to integrate my old rsync habits to create a disaster scenario backup, that selectively (and conveniently) syncs over only the most crucial data that I don't want to live without. I was quite pleased with the outcome so I thought I'd document it for others. Hope it helps!