I've clearly not been keeping up.. Assuming a stripe then we're talking 7-8TB drives?

How much do those cost?

I guess that's a kind of expensive setup for what's being suggested was his home setup though?

20TB in a mirror is cheap as in the DC, at home I've not pushed above about 5 (don't have that much data and thus won't spank so much money on capacity)...

Are you running these things?