Simply put, if it goes down, you're up the proverbial creek without a paddle. It's better to rely on many small servers, balance the load on the servers geographically, and then add more small servers as your demand grows. With the recent development of newer load-balancing machines, you can easily set up a server farm that seems like one single machine to the outside world, but in reality is a series of multiple small servers. Jobs are distributed among these servers by the load-balancing machine and various algorithms can be used for load calculation and distribution. If one server goes down you only lose a fraction of your computing power.
Load balancing technology distributes traffic among a cluster of servers.
This technology is also capable of redirecting client traffic to other servers in case of server problems. It's important that server downtime be invisible to your customers in order to maintain customer satisfaction and loyalty. By utilizing load balancing technology across a server farm platform, you can adjust your back-end operations with minimal ripples for the customer on the front end. And the best part is that the technology does this automatically for the IT manager, rather than requiring you to spend your time mapping individual IP addresses. This means that instead of simply balancing the load evenly over multiple servers at a single location on a LAN, they automatically route traffic to the server with the most available bandwidth, and typically to the closest server, which keeps WAN costs down.