Redundancy is a term often used in computing that refers to multiple copies of data or systems which are stored, with the intention of providing easier access or ensuring recovery in the event of a disaster. Redundancy can be achieved through storage, hardware, or software.
Storage redundancy may be achieved through storing multiple copies of data in multiple locations or storing a single copy of important data in multiple locations. This is done to ensure that resources are accessible in the event of a catastrophe or power failure. Similarly, having multiple copies of the same data may be helpful in cases where a single item is corrupted or lost, thus allowing the user to reference another copy.
Hardware redundancy involves the use of multiple computers or hardware components of the same type, functioning simultaneously in order to assure that the system will continue working in the event of a hardware failure. Each system will constantly checks the other system to make sure it is functioning correctly. If one of the systems detects a problem, it will take over the task from the other system until the problem is fixed.
Software redundancy is the ability to run two or more copies of the same application, thus creating multiple redundancies. This helps to guarantee the continuity of the application if one of the copies fails.
Redundancy can also refer to the idea of using multiple vendors to provide similar services in order to add redundancy and reliability to the system. This means the system is less likely to be impacted by a single vendor outage.
Redundancy is an important aspect of computer system architecture, as it ensures that the system can continue to function even if some parts fail. While this does come with a cost (more hardware, more storage space, etc.), the benefits of a redundant system usually outweigh the cost.
