Physical redundancy (glossary)
a system resilience principle that states that the system should possess two or more independent and identical legs to perform critical tasks. Jackson (2016)
Source
Jackson, Scott. 2016. "Principles for Resilient Design - A Guide for Understanding and Implementation." In IRGC Rresource Guide on Resilience, edited by I. Linkov. University of Lausanne, Switzerland: International Risk Governance Council (IRGC).
Discussion
Also called design redundancy by Leveson (1995)