Global Server Load Balancing (GSLB) is a term used to describe methods for distributing network traffic around the Internet. GSLB is different from Server Load Balancing (SLB) or Application Load Balancing (ALB), as it’s typically used to distribute traffic between multiple data centers, whereas a traditional ADC/SLB is used to distribute traffic within a single data center.
GSLB is typically used in the following situations:
Resiliency and disaster recovery
You have multiple data centers, and you wish to run them in an Active-Passive situation so that if one data center fails, traffic will be sent to the other.
Load balancing and geo-location
You would like to distribute traffic between data centers in an Active-Active situation based on specific criteria such as data center performance, data center capability, data center health check, and the client's physical location (so you can send them to their closest data center), etc.
Commercial considerations
Ensure users from specific geographic locations are sent to particular data centers. Ensure different content is served (or blocked) to other users, depending on several criteria such as the country that the client is in, the resource they are requesting, the language, etc.
