Interview question: design for storing and analyzing big data
In one of the interviews I was asked to design a system which which handles following,
This service gets around 20 million requests per day for storing data. We need to develop a dashboard (graph where x axis is date range and y axis some requests per day with some filter). This should be real time i.e. All requests should be reflected on dashboard with no or little delay. I don't have any experience with big data or NoSQL databases so couldn't give the correct to answer. Since users can select filters on dashboard using relational dbs will not work as joins will be expensive and not fast enough.
How do you solve it? It will be great if someone can explain or point to any useful links.