Satya Nadella, the CEO of Microsoft, once said, “Every company is now a software company.” Take the online food ordering business; for example, digital ordering and delivery have grown 300% faster than dine-in traffic since 2014. During Covid, online ordering grew 3,868% between February and April in large suburbs in the United States. 

As a system architect, I feel that trend every day. More businesses and users are on the internet now, and this activity eventually becomes requests or workloads on a server, an application, and a system. Scalability becomes a challenge. When your server does not have enough resources to handle the increasing load on your application, what do you usually do? Buy more RAM, add CPU cores, and add disks? These solutions are known as vertical scale or scale-up.