Hello,

The UC catalog container is sitting in Sub B.

Basically we have a Spoke and Hub configuration for each Subscriptions. Each Subscriptions can access to any ressource inside it own subscription with some PE. But to access other Subscription ressource, we have to ask an autorisation, and the flow with go from A to B passing by a HUB.

In our casse, A is a DEV environment with DEV data. And B is a production environment with PRD data.

Today we copy data from Storage B to Storage A passing with ADF and a shir, the shir has acces to A and B. But this process is long, and very costly. 
We need PRD dans un DEV env, so that data scientist work with real data and not sample data. They will never have Write access in PRD catalog/database/tables.

This is why we though we could share data from PRD to DEV with unity catalog. Also we do not want to use Delta Sharing since it uses Internet.