Redundancy (engineering)
Electrical surges arising from lightning strikes are an example of a failure mode which is difficult to fully isolate, unless the components are powered from independent power busses and have no direct electrical pathway in their interconnect (communication by some means is required for voting).
The voting method may involve additional complexity if the two things take different amounts of time.
Geographic redundancy reduces the likelihood of events such as power outages, floods, HVAC failures, lightning strikes, tornadoes, building fires, wildfires, and mass shootings disabling most of the system if not the entirety of it.
Geographic redundancy locations can be The following methods can reduce the risks of damage by a fire conflagration: Geographic redundancy is used by Amazon Web Services (AWS), Google Cloud Platform (GCP), Microsoft Azure, Netflix, Dropbox, Salesforce, LinkedIn, PayPal, Twitter, Facebook, Apple iCloud, Cisco Meraki, and many others to provide geographic redundancy, high availability, fault tolerance and to ensure availability and reliability for their cloud services.
Both functions prevent performance decline from exceeding specification limits without human intervention using extra capacity.
One common form of passive redundancy is the extra strength of cabling and struts used in bridges.
Performance decline is commonly associated with passive redundancy when a limited number of failures occur.
Error detection and correction and the Global Positioning System (GPS) are two examples of active redundancy.
A spot network substation uses reverse current relays to open breakers to lines that fail, but lets power continue to flow the airport.
Charles Perrow, author of Normal Accidents, has said that sometimes redundancies backfire and produce less, not more reliability.
This may happen in three ways: First, redundant safety devices result in a more complex system, more prone to errors and accidents.
Third, redundancy may lead to increased production pressures, resulting in a system that operates at higher speeds, but less safely.
[4] Voting logic uses performance monitoring to determine how to reconfigure individual components so that operation continues without violating specification limitations of the overall system.
The simplest voting logic in computing systems involves two components: primary and alternate.
They both run similar software, but the output from the alternate remains inactive during normal operation.
