Читать книгу From Traditional Fault Tolerance to Blockchain - Wenbing Zhao - Страница 30

Once a fault is detected and localized, it should be isolated and removed from the system. Subsequently, the faulty component is either repaired or replaced. A repaired or replaced component can be readmitted to the system. To accommodate these steps, the system often needs to be reconfigured. In a distributed system, it is often necessary to have a notion of membership, i.e., each component is aware of a list of components that are considered part of the system and their roles. When a faulty component is removed from the system, a reconfiguration is carried out and a new membership is formed with the faulty component excluded. When the component is repaired or replaced, and readmitted to the system, it becomes part of the membership again.

A special case of fault removal is software patching and updates. Software faults and vulnerabilities may be removed via a software update when the original system is patched. Virtually all modern operating systems and software packages include the software update capability.