Which metric indicates the percentage of time a system is operational?

Uptime is a critical metric that indicates the percentage of time a system is operational and functioning correctly. It represents the operational performance of a system, ensuring that the service is available to users when needed. Uptime is usually expressed as a percentage, with calculations involving the total time a service is expected to be functional compared to the actual downtime experienced.

This metric is essential for businesses that rely on technology and online services, as it directly impacts user satisfaction and trust. A high uptime percentage signifies a robust system that is consistently available, while low uptime can lead to frustration among users and significant losses for a company.

In contrast, scalability refers to a system's ability to handle growth in users or data without performance degradation. Reliability involves the system's ability to perform its intended function under specified conditions over a defined period, which is somewhat related to uptime but encompasses broader aspects such as failure rates. Quality Assurance pertains to processes and techniques used to ensure that a product meets certain standards and fulfils its intended purpose, but it does not specifically measure operational time.