Load Balancing in the Cloud

Chapter 1. Why Load Balancing Is Important

Load balancing is the act of distributing network traffic across a group of servers; a load balancer is a server that performs this action. Load balancing serves as a solution to hardware and software performance. Here you will learn about the problems load balancing solves and how load balancing has evolved.

Problems Load Balancers Solve

There are three important problem domains that load balancers were made to address: performance, availability, and economy.

As early computing and internet pioneers found, there are physical bounds to how much work a computer can do in a given amount of time. Luckily, these physical bounds increase at a seemingly exponential rate. However, the public’s demand for quick complicated software is constantly pushing the bounds of machines, because we’re piling hundreds to millions of users onto them. This is the performance problem.

Machine failure happens. You should avoid single points of failure whenever possible. This means that machines should have replicas. When you have replicas of servers, a machine failure is not a complete failure of your application. During a machine failure event, your customer should notice as little as possible. This is the availability problem: to avoid outages due to hardware failure, we need to run multiple machines, and be able to reroute traffic away from offline systems as fast as possible.

Now you could buy the latest and greatest machine every year to keep up with the ...