97 Things Every Software Architect Should Know

Chapter 38. Skyscrapers Aren't Scalable

Michael Nygard wrote Release It! Design and Deploy Production-Ready Software (Pragmatic Bookshelf), which won a Jolt Productivity award in 2008. His other writings can be found at http://www.michaelnygard.com/blog.

—Michael Nygard

WE OFTEN HEAR SOFTWARE ENGINEERING COMPARED to building skyscrapers, dams, or roads. It's true in some important aspects.

The hardest part of civil engineering isn't designing a building that will stand up once it is finished, but figuring out the construction process. The construction process has to go from a bare site to a finished building. In the interim, every worker must be able to apply his trade, and the unfinished structure has to stand up the whole time. We can take a lesson from that when it comes to deploying large integrated systems. ("Integrated" includes virtually every enterprise and web application!) Traditional "big bang" deployments are like stacking up a pile of beams and girders, throwing them into the air, and expecting them to stick together in the shape of a building.

Instead, we should plan to deploy one component at a time. Whether this is a replacement or a greenfield project, this has two large benefits.

First, when we deploy software, we are exposing ourselves to the accumulated technical risk embodied in the code. By deploying one component at a time, we spread technical risk out over a longer ...