What is Redundancy in system design?

Updated Apr 28, 2026

Short answer

The duplication of critical components to increase reliability and provide backups.

Deep explanation

Availability and Reliability are the cornerstones of production-grade systems. The duplication of critical components to increase reliability and provide backups. Ensuring high uptime requires both preventing failures and minimizing recovery time.

Real-world example

A website staying up during a traffic spike by using multiple servers.

Common mistakes

  • Assuming a system is reliable just because it is available (e.g., it's 'up' but returns errors).

Follow-up questions

  • How many minutes of downtime is 99.99% availability?

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