Additionally to the classification of faults by appearance, and/or manifestation, this chapter presents in detail types of redundancies one can apply to tolerate a fault in the system. It is argued that redundancy of the designed system should be applied for all three—(1) performancePerformance, (2) reliabilityReliability and (3) energy efficiencyEnergy efficiency of the system. System redundancy therefore must be traded for the sake of all three. We declare that well-designed system must be capable to trade. We demonstrate that system fault tolerance and resilience are not longer static requirements, but on-going processes thought he whole cycle of design and operation of any system. For this, we introduce Generalized Algorithm of Fault ToleranceFault tolerance. Shown how model of system reliabilityReliability should be redesigned, including proposed algorithm.