What are the key differences between vertical and horizontal scaling in system design?

During my final year in college, I worked on a project to design a library management system. We discussed how vertical scaling could be used to improve the performance of our server by upgrading it with more CPU power and RAM. However, we realized that this could limit us in the long run as the budget was a constraint. Instead, we opted for horizontal scaling by designing the system to work with multiple servers, which allowed us to handle more users simultaneously. By the end of the project, we could effectively manage a larger number of transactions without slowing down, demonstrating the practical benefits of horizontal scaling.

While volunteering for a community event, we faced challenges when the number of participants exceeded our initial expectations. Instead of trying to enhance our existing resources, which would be analogous to vertical scaling, we decided to expand our team by recruiting more volunteers. This horizontal scaling approach allowed us to manage tasks more effectively and serve more attendees than we initially planned. By the end of the event, we received positive feedback for our organization, showing how adding resources can often be more effective than just enhancing existing ones.

In my first job at an e-commerce startup, we had to scale our platform during holiday sales. Initially, we relied on vertical scaling by upgrading our main database server to handle the increased load. However, we soon realized that this was a temporary fix and not cost-effective. We transitioned to a horizontal scaling approach by distributing our database across multiple servers. This shift not only improved our system's reliability but also allowed us to manage peak traffic effectively, leading to a significant increase in sales without downtime.