To talk about increasing load and scalability, we first need to define the system’s current load. There is no one way of doing it as it depends on the project and its architecture, but we use load parameters. These parameters will be different for every application.
When we think about Twitter, the load parameter is not how many tweets are posted per second alone because it’s not a high number that requires scaling the whole system. If there are 12000 tweets (write operation) per second, it’s easy to handle. The load parameter for Twitter is the fan-out effect of posting tweets. Each Twitter user follows many people, and each user is followed by many. How to build this system with 12000+ incoming tweets every second is the scalability problem of Twitter.
- Source(s): Designing Data-Intensive Applications by Martin Kleppmann
