You just need one it mode hba sas controller with an external out, and probably a conversion cable from 8088 to netapp’s 8436.

You can daisy chain shelves if needed, and I think you can use a second sas card for active failover but I haven’t tried it.

I’m using a NetApp ds4246 to hold 24 drives, and it’s glorious - embrace the rack mount life. Although my computers themselves are all HP Prodesk minis, which are tiny and amazing, 1 u high and can fit two across on a shelf.