Raid stopped being optimal now that btrfs and ZFS exist.

If you plan on doing matching drives ZFS is recommended

If you expect mismatched disks, btrfs will work.

If you are most worried about stability get a computer with ECC memory.

If you are most worried about performance, use SSD drives.

If you want a bunch of storage for cheap, use spinning disks (unless you exceed the 100TB capacity range)

Your ZFS backup strategy should be to follow one of the following rulesets:

3-2-1 [3 copies of the data at 2 different locations for the 1 purpose of preserving the data]

4-3-2-1 [4 copies of the data at 3 different locations in 2 different types of media for the 1 purpose of preserving the data]

5-4-3-2-1 [5 copies of the data at 4 different locations across 3 different continents in 2 different types of media for the 1 purpose of preserving the data]

The details of the backup is more if you have a second system to enable ZFS send/receive or if you have to transport deltas from ZFS send