Budgeting and scaling

In the AWS Billing section of Chapter 13, Highly Available Cloud Infrastructure on AWS, we covered the monthly costs of operating a web server, ranging from $5/month to $45/month, from a single-server instance scenario to a highly available infrastructure. For most needs, budgeting discussions will begin and end with this monthly number. You can execute load tests, as suggested in the Advanced load testing section, to predict your per-server user capacity and get a general idea of how many servers you may require. In a dynamically scaling cloud environment with dozens of servers running 24/7, this is an overly simplistic way to calculate a budget.

If you operate a web property of any significant scale, things invariably get complicated. You will be operating multiple servers on different tech stacks, serving different purposes. It can be difficult to gauge or justify how much of a budget to spare for seemingly excess capacity or unnecessarily high-performance...