What is defined as the ability for a system to remain operational even if some components fail?

The concept of fault tolerance is defined as the ability of a system to continue operating properly in the event of the failure of some of its components. This means that if one or more components within the system fail, the system can manage the failure and continue to function without interruption. Fault tolerance is achieved through various mechanisms, such as backup systems, redundancy of components, and failover processes. These strategies ensure that the overall system remains operational and accessible to users despite individual component failures, thus safeguarding against downtime and data loss.

In contrast, redundancy refers to the inclusion of extra components that can take over when a primary component fails, but it does not inherently mean the system can handle failures on its own without these backups actively enabled. High availability is closely related, as it refers to a system's ability to be continuously operational and accessible, often leveraging fault tolerance strategies to achieve minimal downtime. Scalability, on the other hand, refers to a system's ability to grow and manage increased loads effectively, which is a different aspect of system design altogether.