Definition
Redundancy is a design approach that provides one or more backup components, paths, or systems so that the failure of a single item does not cause overall system failure: the deliberate elimination of a single point of failure. Its effectiveness depends on the backup being genuinely independent, or common cause failure can defeat it.
Key facts
- The deliberate design response to a single point of failure, adding a functioning alternative path or component.
- Effectiveness depends on true independence between primary and backup, shared vulnerabilities create a common cause failure risk.
- Comes with added cost, complexity, and maintenance burden, so it is applied selectively based on asset criticality, not universally.
- Can take multiple forms: standby equipment, parallel paths, or diverse (differently designed) backup systems for stronger independence.
What does Redundancy reveal about failures?
Redundancy works by providing a functioning alternative (a standby pump, a parallel signal path, a second power feed) that can take over the function of a primary component or path if it fails, so the overall system continues operating without that single item.
How do teams use Redundancy in failure analysis?
Redundancy is specifically designed to eliminate a single point of failure by adding a backup. Its protection depends on the backup being independent of the primary, if both share a vulnerability, a common cause failure can take out both simultaneously, which is why diverse (differently designed or sourced) redundancy is stronger than identical duplicate redundancy against that specific risk.
FAQ
Frequently asked questions
How does an additional path take over the function in case of a failure?
Through redundancy: a backup component, path, or system that can take over the function of a failed primary item, deliberately eliminating a single point of failure, provided the backup is genuinely independent of the primary.
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