redundare

Redundare, or redundancy, is the design practice of incorporating extra components, systems, or data so that the failure of any single element does not interrupt service. The goal is to improve reliability and availability, particularly for critical assets and processes.

Redundancy is used across several domains, including information technology, electrical engineering, transportation, and civil infrastructure. Examples include duplicate power supplies and cooling in servers, multiple network paths, data replication, and geographically dispersed data centers. In data storage, redundancy is implemented through techniques such as RAID and regular backups to prevent data loss.

Common forms of redundancy include hardware redundancy (duplicate components such as power supplies, fans, or network interfaces), data redundancy (replication or parity schemes), and architectural redundancy (multi-node clusters, failover sites). Configurations can be active-active (systems run concurrently and share load) or active-passive (a standby unit takes over when the primary fails), with hot, warm, or cold standby levels indicating how ready the backup is to take over.

Implementing redundancy involves trade-offs between cost, complexity, and risk. While it increases availability and resilience, it also raises capital and operating expenses and may introduce synchronization challenges or potential failure modes if not properly managed.

Key metrics for evaluating redundant designs include availability, mean time between failures (MTBF), and mean time to repair (MTTR). Redundare remains a central concept in high-availability design, helping organizations mitigate single points of failure and maintain continuity of service.