Seagate has introduced the Exos M series, a range of enterprise-grade mechanical hard drives available in 30TB and 32TB capacities. The two models, the 30TB CMR ST30000NM004K and the 32TB SMR ST32000NM003K, each offer a minimum of 3TB per disk and use a standard 3.
A few years ago I had a 12 disk RAID6 array and the power distributor (the bit between the redundant PSUs and the rest of the system) went and took 5 drives with them, lost everything on there. Backup is absolutely essential but if you can’t do that for some reason at least use RAID1 where you only lose part of your data if you lose more than 2 drives.