Welcome back to the System Design series by @mukeshkuiry ! 🚀

Today, we'll dive into crucial concepts for scalable web applications—DNS and Load Balancers.

What is DNS? 🌐

DNS, or Domain Name System, eliminates the need to remember lengthy IP addresses by mapping domain names to IP addresses. Let's simplify it—imagine you're visiting www.google.com. Do you know Google's actual domain address is 172.217.27.174? Entering this IP address each time you visit Google is challenging. DNS resolves this issue by mapping the IP address with a straightforward domain name; for Google, it's www.google.com.

Imagine millions of users accessing Google simultaneously. Due to server limitations, handling this traffic is challenging. Here, DNS Load Balancers come to the rescue. Google deploys multiple servers with different IP addresses, all mapped to the same domain name. The DNS Load Balancer checks server loads in real-time and directs users to the least busy server, optimizing performance.

What is a Load Balancer? ⚖️

Load balancing is pivotal for scaling efforts, ensuring effective scalability with rising traffic while maintaining high availability. Load balancers, acting as reverse proxies, distribute network traffic across multiple servers using various algorithms. This distribution prevents the risk of overwhelming a single machine or a few machines in the cluster with all the traffic.

Load balancing is crucial for avoiding issues. If a server goes down during user request processing, the load balancer automatically redirects future requests to functional servers.

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