Single point of failure
SPOF · Единая точка отказа · Точка отказа
A component whose failure brings down the whole system. The classic structural fragility. Almost always cheaper to remove than to defend.
One database without a replica. One key person who knows the production secrets. One supplier for 80% of revenue. One income source. A system with even one SPOF behaves robustly almost all the time - until it doesn't, and then it fails catastrophically. The cost of being wrong about "this'll be fine" is asymmetric.
Most «black swan» disasters in companies, careers, and lives are SPOFs that the owner knew about and didn't address.
A freelancer with one client doing 70% of their income. Everything is fine. The client leaves. Everything is not fine.
- 1Audit your system. List the components. For each: «what happens if this fails completely?» Anything with answer «we're done» is a SPOF.
- 2For each SPOF: redundancy, replacement plan, or shutdown plan. Pick one.
This part of the knowledge base is inspired by the book. Go to the Ukrainian edition to explore the concept in depth.
- · Антипаттерны антихрупкости - single point of failure