What is DNS Load Balancing?
DNS-based Load Balancing is the practice of configuring a domain in the Domain Name System (DNS) such that client requests to the domain are distributed across a group of servers. A domain can correspond to a website, a mail system, a print server, or another service that is made accessible via the Internet. It facilitates faster access to a domain by providing several IP addresses for a single host or domain name, which routes traffic between two or more servers.
DNS-based Load Balancing helps optimize client requests for a specific domain. It can incorporate several techniques that are used to distribute, redirect or manage the overall load balancing process of clients issuing requests to a domain including:
- Backup server: A clone instance of a domain is created to serve as a secondary DNS. The primary DNS may redirect traffic to this server at runtime.
- Round robin DNS-based load sharing: DNS requests are rotated and shared across multiple domain server instances. Although mainly a load sharing algorithm, this also facilitates load balancing with DNS.
- Dynamic DNS load balancing: DNS requests are routed between domain servers with the best available resources and minimal load.