Problem statement

Let’s start with a simple question. Can we make a software application without using databases? Let’s suppose we have an application like WhatsApp. People use our application to communicate with their friends. Now, where and how can we store information (a list of people’s names …

System design problems usually have some similarities, though specific details are often unique. We have extracted these similarities across design problems as the basic building blocks we’ll be covering. One example of a building block is a load-balancing component, which we’ll probably use in every design problem in …

The origins of DNS

Let’s consider the example of a mobile phone where a unique number is associated with each user. To make calls to friends, we can initially try to memorize some of the phone numbers. However, as the number of contacts grows, we’ll have to use …

Through this lesson, we’ll answer the following questions:

• How is the DNS hierarchy formed using various types of DNS name servers?
• How is caching performed at different levels of the Internet to reduce the querying burden over the DNS infrastructure?
• How does the distributed nature of the DNS infrastructure …

What is load balancing?

Millions of requests could arrive per second in a typical data center. To serve these requests, thousands (or a hundred thousand) servers work together to share the load of incoming requests.

Note: Here, it’s important that we consider how the incoming requests will be divided …