As a PSA: depending on your needs (bcs I see a lot of simple homelabs RAIDing), consider second server or even second location simple snapshot backup vs same-machine duplication.
Like, which would you want to set up first depending on your specific risks profile.

The later is like like a proper backup, the former more of a low-downtime strat (that most smol homelabs can do without - "just wait a day, mom")

Eg as the most basic example - instead of local duplication you could have a small PC (even like some old Pi), big HDD, and rsync once a day.

(Ofc, with duplicated serves, finances permitting, you can also provide backup services which helps that downtime issue. And by finances I mean the rest of your server group stuff, which in my cases is mostly HDD cost anyways.)