with two drives (preferably different brands/age, HDD or SSD doesn’t really matter) in it using a checksumming filesystem like btrfs or ZFS so that you can do regular scrubs to verify data integrity.
an important detail here is to add the 2 disks to the filesystem in a way so that the second one does not extend the capacity, but adds parity. on ZFS, this can be done with a mirror vdev (simplest for this case) or a raidz1 vdev.
Max_P