An average server takes a beating over the years. Hosting websites, fighting off attacks, and simply staying on 24 hours a day and 7 days a week can wear down even the best servers. Furthermore, as a server’s users grow, and the websites it hosts become more popular, increased traffic can cause higher load averages, connection difficulties, and even system crashes.
For a server that gets low or average traffice, this may not be a problem, but if you have a server that receives heavy traffic, you might want to consider having at least one redundant server. This is essentially a server with identical data that shares the user load. When too many users start accessing one server, the other server will balance the load (a practice called load balancing).
Another advantage of redundant servers is to minimize downtime. If you need to perform maintenance, upgrades, etc., you can temporarily take one server offline, while the other one takes over the responsibilities of the first.
The final and most important reason to have redundant servers is that wear and tear I mentioned above. If your server goes down, you will have unhappy customers, or at the very least, you will be unhappy. With redundant dedicated servers, you can make sure all of your sites stay active, even if one server breaks down. Preparing for disaster before it happens is a great way to protect yourself and your users/customers. Server redundancy is one way to make that a reality.