Oh man I’m gonna show my lack of knowledge too 🙂. I’ll try anyway, but take everything I say with a grain of salt.
There are different types of RAID, but I believe RAID 1 would be a mirrored array. This Lemmy instance is on a ZFS mirrored array, but that’s handled by the host so I don’t have to understand it 🙃. I am not sure if the ZFS mirror is considered RAID but it’s basically the same thing as RAID 1 (perhaps one is hardware one is software based?)
I see this setup as more of a redundancy for a live system so it can continue with one of the drives after a failure without downtime, and I probably wouldn’t consider the mirrored drive a backup. But I’m no expert!