Fault Tolerance

Definition of fault tolerance in The Network Encyclopedia.

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What is Fault Tolerance?

Any mechanism or technology that allows a computer or operating system to recover from a failure. In fault tolerant systems, the data remains available when one component of the system fails. Here are some examples of fault tolerant systems:

  • Transactional log files that protect the Microsoft Windows registry and allow recovery of hives
  • RAID 5 disk systems that protect against data loss
  • Uninterruptible power supply (UPS) to protect the system against primary power failure

Just because your system is fault tolerant doesn’t mean you are fully prepared for disaster. You still need to perform regular backups of important data. For example, a RAID 5 disk system will protect against data loss if one disk drive fails, but not if two or more drives fail simultaneously.