Help with Deduplication

Hi Everybody 

I write on this forum because I have a doubt with the Backup Exec Deduplication option.

I have a customer who wants to deduplicate 10 Tb of data to cloud and I can´t find a document that help me on understand how much capacity does my customer needs to have on the on-prem storage. 

¿My question is if my customer needs to have 10 Tb of dedupe capacity On-Prem and 10 Tb of dedupe capacity On-Cloud?

I´ll appreciate your help.

Regards