Because no one technique necessarily accommodates all the needs of your environment, you may need to use more than one design technique.

For example, if you have a site that uses data for decision support applications, but requires no updates to data, you can use a fault-tolerant peer-to-peer and cascade scenario, as shown in the following illustration.

Data from San Francisco is replicated to Los Angeles on a peer-to-peer basis and to New York on a protected read-only cascade basis. Data from Los Angeles is replicated to San Francisco on a peer-to-peer basis and to New York on a protected read-only cascade basis. In the event of a failure at New York, decision support is performed at either San Francisco or Los Angeles with a degree of performance impact.