The number of requests for information from the center's Web server has increased continuously. As of this writing, the NCSA Web service receives more than 500,000 requests each weekday. This phenomenal load has present-ed a significant technical challenge. No ordinary computer is designed to respond to 30 network requests per second for several hours at a time, and not many computers can do this at all. As the load has grown, individual computers used as servers have struggled and, inevitably, failed under this unprecedented stress.
Any single computer has an upper limit of Web traffic it can handle.
Our load already exceeds the limit for most computers. We quickly realized that we needed to use more than one computer to meet the demand. The NCSA solution can be applied to other situations. Starting with one server in February 1994, we had four servers in May, six in September, and eight in December. NCSA will continue to add servers throughout the coming months and, possibly, years.