Vertical scaling and horizontal scaling are two different ways to increase the capacity of a system to handle more traffic or data. Vertical scaling, also known as “scale-up,” involves adding more power to a single server, such as by increasing its CPU, RAM, or other resources. Horizontal scaling, on the other hand, involves adding more servers to the system, effectively creating a pool of resources that can be used to handle the increased workload.

One of the main advantages of vertical scaling is its simplicity. It is often easier and faster to add more resources to a single server than to add new servers to the system. However, vertical scaling has some significant limitations. For one, there is a hard limit to how much you can add to a single server. It is not possible to add unlimited CPU and memory to a single machine.

Another major limitation of vertical scaling is its lack of failover and redundancy. If a single server goes down, the entire system can go down with it, leading to downtime and potentially lost revenue. In contrast, horizontal scaling allows for the distribution of workloads across multiple servers, providing failover and redundancy to prevent downtime in the event of a server failure.

Overall, horizontal scaling is generally considered a more desirable approach for large-scale applications that need to handle a lot of traffic or data. One way to implement horizontal scaling is through the use of a load balancer, which distributes incoming traffic among the available servers in the system. This can help prevent slow response times or server overload, ensuring that users can access the website or app even when traffic is high.