They have already added a second processor in each load balancer and are planning to add more load balancers for additional growth. Another factor Torborg considered was product licensing. In his situation, the WebSphere's pricing per load-balancing box was optimal for supporting 60 Web servers. The product's weakness is in the area of manageability. Torborg's team needed to build their own user interface to add and manage clusters.
Management is an ongoing cost.
Before you choose a load-balancing product make sure you understand your scalability and redundancy requirements and understand how the product is licensed, Torborg advises. Subra Kumaraswamy, network architect at the Waltham, Mass., firm, says DNS round robin techniques work well if you only have a few servers. Although DNS is effective in most cases, it's not a reliable solution for large-scale sites because there is the possibility that traffic could be directed to a downed server. Feeling an immediate need for load balancing, Kumaraswamy didn't have the luxury to do an orchestrated product evaluation. He did a lot of paper research on the Web and narrowed his search down to Alteon's ACEdirector and Cisco's Local Director.