All of Stack Exchange on only 25 servers?

Stack Exchange runs many QA sites, including Stack Overflow, an Alexa top 100 website. It’s amazing to read how such a popular website with millions of visitors can be handled by only a couple dozen servers. They have adopted a scale-up approach to building out their infrastructure with best-of-breed components. Many components are .NET and Windows-based (IIS web servers and SQL Server databases), but there’s a healthy amount of *nix as well (Redis, Elastic Search, and HAProxy). Servers are loaded with at least 96GB of RAM, 1 Gb network connectivity (but 2 x 10 Gb for SQL!), and lots of SSD. It’s a fascinating read. My takeaway is that to eke the best performance: run on bare metal and optimize with software.

Read - What it takes to run Stack Overflow « Nick Craver