In cloud computing, what does "scalability" refer to?

Scalability in cloud computing refers to the ability to adapt the computing resources according to demand. This means that as the workload increases or decreases, the cloud infrastructure can automatically adjust its resources. For instance, during peak usage times, additional virtual machines can be provisioned to handle the load, and during off-peak times, resources can be scaled back down to save costs. This dynamic adjustment is a core advantage of cloud computing, allowing organizations to efficiently manage their resource utilization and costs while ensuring that they can meet user demands without excessive investment in physical hardware.

The other options present different concepts unrelated to the core definition of scalability. For example, while increasing hardware capacity without downtime is related to high availability and redundancy, it does not encompass the complete flexibility that scalability provides. Additionally, securing a cloud environment from attacks relates to security practices, which, while important, is a separate concern from the elastic resource management that scalability involves. Finally, the notion of supporting only fixed resources contradicts the fundamental principle of scalability, which focuses on flexibility and adaptation to changing workloads.