Vertical Scaling
Vertical scaling, also known as scaling up, involves adding more resources such as CPU, RAM, or storage to a single machine to handle increased loads. This approach is typically used in traditional monolithic applications where the system is running on a single server or node. While vertical scaling is relatively straightforward and does not require significant changes to the underlying architecture, it has its limitations. As the system grows, there is a point where the physical resources of a single server are exhausted, making further scaling more challenging and costly. This form of scaling is often used for databases like MySQL or PostgreSQL where database administrators opt to increase the resources of the server rather than distribute the load across multiple nodes.
https://en.wikipedia.org/wiki/Scalability
A major advantage of vertical scaling is its simplicity in implementation. Since it does not require significant changes to the architecture or complex configurations like horizontal scaling, it can be the faster option for smaller systems that experience moderate growth. Additionally, applications that are designed to run on a single server or where data consistency is paramount often benefit from vertical scaling as it reduces the complexity of managing distributed systems. For example, adding more CPUs or upgrading memory in a server running a web server or application server can help increase throughput without having to re-architect the entire system.
https://en.wikipedia.org/wiki/Scalability
However, vertical scaling does come with significant challenges as systems scale. Once a server hits its physical limits, further scaling becomes difficult and expensive. In these cases, a shift to horizontal scaling might be necessary, especially for large-scale applications or services with unpredictable growth. Unlike horizontal scaling, which can distribute the workload across many nodes, vertical scaling only increases the capacity of one machine, creating a potential single point of failure if the server goes down. While it can be an appropriate short-term solution, organizations planning for long-term growth might eventually need to combine vertical scaling with horizontal scaling strategies, particularly in cloud-based environments that support elastic scaling.