Elasticity VS Scalability

In today’s article, we will explore the concepts of elasticity and scalability, which are similar in definition but distinct in practice.

As software developers, we frequently encounter terms like “scalable” and “scalable systems.” You might have also considered whether the code you write or the approach you take in designing a system—be it a mobile or web application—is scalable. In simpler terms, scalability refers to the ability of your code or approach to efficiently serve a large number of users by maximizing output while minimizing resource usage.

Consider a web application you’ve developed for your startup to address a specific problem and serve multiple users. Initially, the application may not have many users, resulting in a manageable load. However, as the application grows, you must accommodate the increasing traffic. One approach is vertical scaling, which involves upgrading the server components hosting your application. Alternatively, horizontal scaling involves increasing the number of servers by creating multiple instances and using a load balancer to distribute the load optimally, preventing any single server from becoming overwhelmed.

On the other hand, elasticity refers to the server's ability to handle sudden spikes in traffic, whether unexpected or due to planned events. For example, during Flipkart’s Big Billion Days, there is a surge in users visiting the application and placing orders, leading to numerous searches, filters, and transactions—essentially millions of requests to the server. During such times, the server automatically scales up to manage the increased load and scales down as the load decreases. This is often achieved through serverless computing, where the server adjusts its capacity based on demand, and you only pay for the resources used, eliminating the need for manual allocation.

While scalability and elasticity may sound similar, they are distinct. Scalability involves increasing server instances or upgrading components to handle growing user numbers, whereas elasticity focuses on temporarily scaling up and down in response to sudden traffic spikes.

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Swarga codes