The monolith approach is simple, and you can just add more web servers to handle additional users. However, this approach can become cumbersome, as an application (and the development team) grows larger because the slightest change requires a full redeployment to each web server.
In addition, a monolith is easy to scale vertically (up) but hard to scale horizontally (out), which we covered previously. However, a monolith is easier to debug, so you need to be careful and have good monitoring and logging. You don't want any random outage investigation to turn into a murder mystery hunt because of unnecessarily implemented microservices.
Historically, Facebook had a deployment process that consisted of slowly compiling ...
