Design a database system for a library, incorporating the following entities: books, authors, genres, shelves, and borrowing records? Develop an Entity Relationship Model that outlines the attributes of each entity, primary and foreign keys, and illustrate the relationships between all entities. Consider storage and performance implications in your design, as the final evaluation will be based on the optimal solution, acknowledging that there may be multiple valid approaches.

Note: you may draw by hand, or using other tools for ER design. When done, upload your image.