What term describes adding more servers to a cluster to improve application performance?

The term that describes adding more servers to a cluster to improve application performance is known as horizontal scaling. This approach involves increasing the number of machines or servers in a system to enhance performance and handle a larger workload. When you horizontally scale an application, you distribute the requests or data processing across multiple servers, which can lead to improved load distribution and fault tolerance.

Horizontal scaling is particularly beneficial in environments where high availability and responsiveness are critical, as it allows applications to manage increased traffic seamlessly. By adding more servers, you can ensure that no single server becomes a bottleneck, thus enhancing overall performance.

Vertical scaling, on the other hand, involves upgrading the resources (CPU, RAM) of an existing server, rather than adding new machines. Caching refers to storing frequently accessed data in a temporary storage area to speed up retrieval times, and redundancy involves having backup components or systems in place to ensure reliability but does not specifically focus on improving performance through the addition of servers.