Which software architecture support large scale data with efficiency and easy to support?

I have been using Repository pattern with unit of work MVC 5 with Angular js and Linq to Sql in past but my project I selected is of very large scale data .

I need efficiency of system but in current pattern Repository Pattern with LINQ its not easy to support and maintain the system . When data increases in size even you apply paging to show some of data it won't work as perfectly as tables are more then 200 in number so managing DTO making single , reverse dto and mapping most of the time effect support team due to recursion so it dependency effect the entire system.

So please guide me can i use Store Proc with LINQ or ADO.NET for developing my API's . Also I want to store documents in database is it good Idea or i use server space.

Is there any other design patter or architecture that will help me to get rid of my problems.So i can easily manage classes , changes after deployment , large scale data , documents and fast in response time .

Please share view related to front end and back end and Database