I'm running 4 20TB barracudas i got last summer in a RAID 10 for my truenas. I'd do it more efficiently if I had planned with enough space to move the data and redo the RAID, this raid has existed for almost a decade. It's reliable, used daily (24/7 uploads in soulseek), currently sharing out 36 TB of movies/music/tv series around 1TB data upload per day.