Where has all my storage gone?

Since Drobo doesn’t want to give us any usage information in the Dashboard, what is the easiest way to tell what share and sub folder of that share is taking up the most space?

I know of ncdu however it takes forever to run. Yes, I know I’m dealing with 10TB of data.

Dear Drobo, Please add a usage screen that tells us Volume Usage, Share Usage and the top level of that share.