Redundancy
Redundancy typically refers to the duplication of hardware or software so that more resources are available for execution. For example, it's possible to have redundant Web servers or redundant disk drives, such as RAID. With either, the redundancy not only increases the ability of a system to scale, it also increases reliability—if one of several Web servers crashes, a Web site remains accessible.
Note that redundancy, as used here, is not the same as replication. The former refers to the duplication of resources, the latter refers to the duplication of data.
There can be a performance benefit to redundancy, depending on the resource involved. Consider a Web server farm. By replicating the number of Web servers, we can effectively ...
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