What role does DNS routing play in ensuring server availability and traffic distribution?

DNS routing plays a key role in ensuring availability and distributing traffic among servers. It allows directing user requests to different IP addresses based on DNS settings, which helps:

• Ensure fault tolerance: if one server is unavailable, DNS can redirect traffic to another.
• Load balancing: distribute requests among multiple servers, reducing the load on each.
• Geographical distribution: direct users to the nearest server to reduce latency.

An example can be using A records with multiple IPs or using DNS with geolocation support (GeoDNS). This is a simple and effective way to scale and increase the reliability of services.