I currently use Time Machine with a Time Capsule to manage my immediate local machine backups. Seeing as how Time Machine likes to periodically invalidate backup sets, this isn't a viable long-term option. I also use BackBlaze for off-site backups, but given it's policy for only maintaining deleted files for 30 days, it's not a long-term option either. In a nutshell, here's what I need: One-way (possibly incrememtnal) backup to a large NAS that *never* removes files from the destination Ability to incrementally update backup periodically when connected to local network, and also immediately after reconnecting to local network Data integrity validation is a plus I had something that fit this well when I was on Windows, but since moving to OSX, I haven't found a viable solution. I've meddled with using rsync, but I'd like a more polished ad well-tested solution if possible (without having to roll my own).