Scalable Internet Architectures

High Availability

Because high availability was the first item in the previous list, the first thing in your mind might be: “What about load balancing?” The criticality of an environment has absolutely nothing to do with its scale. Load balancing attempts to effectively combine multiple resources to handle higher loads—and therefore is completely related to scale. Throughout this book, we will continue to unlearn the misunderstood relationship between high availability and load balancing.

When discussing mission-critical systems, the first thing that comes to mind should be high availability. Without it, a simple system failure could cause a service interruption, and a service interruption isn’t acceptable in a mission-critical environment. ...