In the Internet environment, service availability is far more relevant than any individual system element or application. By deploying cost-effective redundant servers, you can treat individual servers as field replaceable units and use failover technologies to ensure that customers don't experience service interruptions even in the event of a system failure. And the money you save on hardware, you can plow back into features and applications that add value to your customers and differentiate your services in a highly competitive marketplace. Scaling up is particularly well suited to the back-end, where the rate of change is slower and the application mix is more stable. Companies can scale up by adding larger systems or by increasing the number of processors or memory within a given system.
Businesses can also intermix the two models.
And Challenges To date, the most urgent needs for scalability have been felt at the front-end. Now, with the Third-Generation Internet Business emerging, the pressure will grow even more intense. Powerful servers will present information to customers in the form the customer needs it, using flexible industry-standard interfaces and loosely coupled applications, and providing unequalled abilities to integrate, automate and personalize information. In times of rapid change, the best strategy is one that preserves your flexibility and gives you room to grow.