Great, so let's start repeating http://www.justfuckinggoogleit.com stuff over and over again to get this forum flooded with useless posts? Data mirroring (RAID-1) without using recent filesystems that ensure data integrity is plain stupid. Reasons can be found on the net and on this forum eg. https://forum.armbian.com/index.php/topic/2921-software-raid-on-opi-pc/
Let's stop here. Everything is already said thousand times. Let's stop writing and start reading (do some Google-Fu before). And please try out the following to get the idea how a data mirror correlates with 'data safety'. Just do a 'sudo rm -rf /' on your SBC and then educate yourself what snapshots are and how they prevent from a situation where everything is lost when using stupid RAID modes.
