What does scalability refer to in a system?

Scalability in a system refers to its ability to adjust performance and cost based on demand. This means that as the usage of a system increases—whether through more users, data, or transactions—the system can effectively manage this increase without significant degradation in performance.

For example, a scalable web application might handle extra user traffic by distributing the load across multiple servers or by utilizing cloud resources that can be provisioned to match demand. When demand decreases, resources can be scaled back, ensuring cost efficiency. This dynamic adjustment is crucial for maintaining operational efficiency and affordability, particularly in environments with fluctuating workloads.

The other options do not accurately reflect the concept of scalability. Increasing software features or enhancing user interfaces might improve user experience or functionality but does not necessarily relate to the handling of varying load levels in a system. Maintaining data integrity is essential for reliability but does not pertain to the ability to adjust to user demands in terms of performance and resource allocation.