What describes the inclusion of extra components not essential for operation but present to prevent failure?

The concept of including extra components that are not essential for operation but are present to prevent failure is best described by redundancy. Redundancy is a design principle used in various systems, particularly in IT and data center environments, where additional resources—such as servers, power supplies, or network connections—are put in place to kick in if the primary component fails. This ensures that the system can continue to operate without interruption.

By incorporating redundant components, organizations can enhance their resilience to failures, minimizing downtime and ensuring that services remain available even in the event of hardware or software malfunctions. This approach is foundational to building robust systems that can withstand unexpected issues, as it provides backups that can take over seamlessly when needed.

High availability, while related to the idea of maintaining service during failures, focuses more on the overall system design and uptime guarantees rather than specifically referencing extra components. Fault tolerance involves the ability of a system to continue functioning correctly even in the presence of faults, but it typically implies built-in capabilities rather than just added redundancy. Overprovisioning refers to allocating more resources than necessary to handle peak usage, which does not inherently focus on preventing failures like redundancy does.

Thus, redundancy is the most accurate term for describing the practice of including non-essential