Drobo

Tool to measure Share size

Overnight my 5N went from 25% free capacity to “full”.
I’m trying to measure the size of each Share.
Doing so on MacOS is sloooow.
Is there a proper tool out there to measure the size of each (mounted) share volume?

I should have approx 7Tb of data, whereas the Drobo says all 10Tb is full/