Can we have a discussion on designing this sevice which is fast and scallable and highly available.

1. A book can have different formats - (pdf, doc).
2. The ui app will have a search bar or an advanced form for filtering and querying results.
3. book can be searched using authors name, book name, book number.
4. It would be nice if we can also retrive top 20 relavant result based on the phrase query string that user has typed to search. This concept is related to information retrieval, tfidf score, cosine similary. we can discuss better approach also.
5. Books will have cover photos as well
6. .... can add more interesting features

...

Can we discuss the HLD and LLD of this service.