SFF drive array 2

https://kilo-wiki.win/index.php/Choosing_the_Right_Storage_for_Virtualization_in_the_Data_Center

The SFF drive array is a compact storage solution where multiple small-form-factor hard drives or SSDs are stacked in a tight chassis, ideal for servers or home labs where every inch of rack space matters. Its dense layout can cram terabytes of capacity into a 2U or less enclosure, but you have to plan ahead for cable management and airflow, since those little drives generate heat fast when under load.