My favorite interview question to ask candidates is: “What happens when you type www.(amazon|google|yahoo).com in your browser and press return?”
While the actual process of serving and rendering a page takes seconds to complete, describing it in real detail can take an hour. A good answer spans every part of the Internet from the client browser & operating system, DNS, through the network, to load balancers, servers, services, storage, down to the operating system & hardware, and all the way back again to the browser. It requires an understanding of TCP/IP, HTTP, & SSL deep enough to describe how connections are managed, how load-balancers work, and how certificates are exchanged and validated… and that’s just the first request!
Web Performance & Operations is an emerging discipline which requires incredible breadth, focusing less on specific technologies and more on how the entire system works together. While people often specialize on particular components, great engineers always think of that component in relation to the whole. The best engineers are able to fly to the 50,000 foot view and see the entire system in motion and then zoom in to microscopic levels and examine the tiny movements of an individual part.
With websites, the introduction of change (for example, a bad database query) can affect (in a bad way) the entire system, not just the component(s) that saw the change. Adding handfuls of milliseconds to a query that’s made often, and you’re now holding page requests up longer. The same thing applies to optimizations as well. Break that [bad] query into two small fast ones, and watch how usage can change all over the system pretty quickly. Databases respond a bit faster, pages get built quicker, which means users click on more links, etc. This second-order effect of optimization is probably pretty familiar to those of us running sites of decent scale.
Working with these systems requires an understanding not only of the way technology interacts, but the way that people do as well. The structure, operation, and development of a website mirrors the organization that creates it, which is why so many people in WebOps focus on understanding and improving management culture & process.
Organizing a conference like Velocity is a wonderful challenge because it requires the same sort of thinking. We focus on the big concepts that everyone needs to know and then go deep into the technologies that change our understanding of the system. We find ways to share the unique experience that can only be gained by operating at scale. We make it safe to share as much of the “Secret Sauce” as we can.