What are the benefits of horizontal scaling compared to vertical scaling?

Horizontal scaling, often referred to as scaling out, involves adding more machines or nodes to a system to distribute the load and improve capacity. This approach has significant advantages in terms of flexibility in resource allocation. As demand fluctuates, organizations can add or remove nodes to ensure that resource allocation aligns with current needs without the limitations imposed by a single machine's capacity. This adaptability allows businesses to respond quickly to changes in user demand or application requirements.

In contrast, vertical scaling, or scaling up, typically involves enhancing a single machine's resources, such as upgrading its CPU, RAM, or storage. While this may seem straightforward, it limits flexibility because there’s a maximum capacity for how much a single machine can be upgraded. Once a machine reaches its limits, vertical scaling becomes impractical and costly.

Moreover, horizontal scaling enhances redundancy and higher availability, as workloads can be distributed across multiple nodes. If one node fails, the system can continue functioning effectively by utilizing the remaining nodes. This versatility makes horizontal scaling a sought-after option for cloud architectures and microservices, where agility and responsiveness to changing demands are critical.

Thus, better flexibility in resource allocation highlights why horizontal scaling is often preferred in scenarios requiring scalability and efficiency.