degradedmode

Degraded mode is a term used in technology and systems engineering to describe a state in which a system continues to operate after one or more components have failed or performance has degraded, with only a subset of capabilities available. The goal is to preserve essential functionality and service continuity while avoiding a complete shutdown. Degraded mode is distinct from failover or fully fault-tolerant operation, because it accepts reduced performance or feature availability rather than an automatic switch to an alternate system.

Triggers for entering degraded mode include hardware failures, software faults, network partitions, power losses, or planned maintenance. In critical systems, degraded mode may be activated to maintain safety and prevent cascading outages. The precise criteria for entering degraded mode are typically defined in system design documents and may depend on component health, load levels, or service priorities.

Common characteristics of degraded mode are reduced throughput, higher latency, a smaller feature set, partial data access (such as read-only modes), and increased error rates. Systems in degraded mode often rely on monitoring and automated indicators to alert operators, who may then take corrective action or initiate manual remediation. Documentation and runbooks usually specify how degraded mode affects user experience and how to transition back to normal operation.

Examples span various domains. In IT networks, degraded routing or limited bandwidth may persist during partial outages. Storage systems may operate in read-only mode. Databases might restrict writes to preserve integrity. In automotive or aerospace contexts, limp mode or degraded operation allows a safe return to a serviceable state despite faults.

See also: graceful degradation, fault tolerance, and community-run recovery procedures.