DracoMac

URE is FUD. Enterprise drive, 10^16 now, not 10^15. Seagate Exos, WD Ultrastar, real specs. You buy cheap NAS drive, your funeral. Good hardware RAID controller, patrol read, scrub monthly. Risk managed.

20TB drives at $15/TB is steal. RAID 5 gives 80% usable. Mirror is 50% deal. Price-per-GB wins. Free trials of rebuild stress exist? No. Suspicious. But math is math. 4x20TB RAID5 = 60TB usable. 4x20TB mirror = 40TB. 20TB difference pays for hot spare.