What type of scaling is achieved by adding more memory and processor cores to a virtual server?

The correct choice corresponds to vertical scaling, which refers to the process of increasing the capacity of a single server by adding more resources such as memory and processor cores. This approach enhances the performance of that particular machine, allowing it to handle increased workloads and process more tasks simultaneously without the need to distribute the load across multiple servers.

Vertical scaling is often straightforward because it involves upgrading the existing hardware of a single server, making it easier to manage in certain contexts. However, it does have limitations, such as a potential maximum capacity for resources that the server can handle and possible downtime during upgrades since the server may need to be powered down.

In contrast, horizontal scaling involves adding more machines or servers to the infrastructure to share the load, which can enhance the system's availability and resilience. Redundancy relates to having backup components to provide reliability, while caching is about storing frequently accessed data for quick retrieval. These concepts are different from the direct addition of resources to an individual server.