At the core of modern web-scale applications is ease of access on the internet. Choose any name of a business, social network, or publication, wrap it up with a .com at the end and type that into a browser. The most likely thing to happen is a website belonging to that company, newspaper, TV channel, or social network will pop up. DNS is probably a technology everyone using the internet uses multiple times per day without even knowing it. And it is becoming crucial for both making the application respond on the internet, as well as giving the application the ability to be highly available, resilient, and scalable.
Traditional DNS servers map IP addresses to FQDNs in zone files. These are stored in text or binary format (binary can help with performance). Lots of times, these files are stored on one master server and one or more slaves. The master is where...