Top 15 Memory eaters in mount level



I’m new to unix. Could you help me in solving my issue.

My requirement is I need to pull Top 15 users (storage) in every mount. I could able to get the mount level information but I couldn’t able to pull the top users in every mount. I see in every mount I could see a lot of nested folders.

For example; If I looking to mount A in this I could see folder A folder B folder C and again in each folder i,e Folder A i could one more folder A1. This is where my data sets are available.

Totally i have around 20 mount point (approx).

Could you help me to solve my problem getting top 15 users who eat space.

Regards, Sam