Automatic or manual failover

Worked examples, recomputed

Every number the mechanisms quote for this relationship is recomputed from it, so none of them disagrees with it.

• 1 failure a year × 20 min saved = 20 min
• 4 false alarms × 3 h = 720 min of damage

Where it appears

Each mechanism states it in its own names. The general symbol each name stands for is shown with it.

• Fault Tolerance & Delivery Semantics

  What is the cheapest thing that can be safely done twice?

  $$P(\text{real})\times \text{saved}>P(\text{false})\times \text{cost}$$

  Read it in place →