Global Server Load Balancing

<< Back to Technical Glossary

Global Server Load Balancing Definition

Global server load balancing (GSLB) is the act of load balancing across globally distributed servers. This allows distribution of traffic to be performed efficiently across application servers that are dispersed geographically.

Diagram depicts global server load balancing where load balancing is globally distributed across different servers. This allows distribution of traffic to be performed efficiently across application servers that are dispersed geographically.

What is Global Server Load Balancing?

Global server loading balancing (GSLB) refers to web traffic management and application delivery over multiple data centers and/or public or private clouds in various geographical areas. Application load at each location is typically managed by “local” load balancers, and client requests are generally sent to closer servers to ensure minimal latency and maximum performance.

How Does Global Server Load Balancing Work?

Let’s examine what happens when a client HTTPS request is sent to a website that uses global server load balancing. First, a main server obtains the client’s IP address and analyzes information about the client’s location. Simultaneously, the server performs health checks to assess the real time performance and responsiveness of the servers. Finally, the main server forwards the request to the local DNS server that is nearest geographically or has the shortest response time. All of this happens behind the scenes within split seconds.

Is Global Server Load Balancing Open Source?

Enterprises can find open source global server load balancing solutions online, but the highest performing GSLB services are generally integrated with application delivery solutions with commercial support.

What Are the Benefits of Global Server Load Balancing?

GSLB is usually implemented to achieve one or more of the following goals for an application:

Performance: Passing user requests to the nearest servers minimizes network latency and network issues. GSLB ensures optimal website or service performance to clients in geographically distributed areas.

Customized Content: GSLB allows enterprises to host content on local servers that is customized for relevance in that geographic location and language.

Disaster Recovery: Application high availability minimizes the impact of data center or network failures. For instance, if a power outage affects California, the load balancer will redirect client requests to other servers hosted in multiple sites that are spread apart geographically.

“Cloud Bursting”: If applications are hosted in hybrid clouds, the GSLB system can “burst” to a public cloud to absorb unusually high load.

Maintenance: Data center migrations and upgrades can be executed in a non-disruptive manner, since the client requests can simply be redirected to servers elsewhere.

Compliance: GSLB makes it easier to adhere to government regulations, especially if the website or services serve tightly regulated industries like defense, telecommunications or healthcare. Local servers and GSLB forwarding preferences can be customized to comply with country-specific regulations.

Does The VMware NSX Advanced Load Balancer Offer Global Server Load Balancing?

Yes. The VMware NSX Advanced Load Balancer delivers modern load balancing, including an entirely innovative way of handling global server load balancing functionality (GSLB) for enterprise customers. VMware NSX Advanced Load Balancer supports:

• Active / Standby data center traffic distribution
• Active / Active data center traffic distribution
• Geolocation database and location mapping
• Data center persistence
• Rich visibility and metrics for all transactions
• Integration with public clouds to support GSLB

For more on the implementation of load balancers, check out our Application Delivery How-To Videos and watch the Global Server Load Balancing How To Video here:


For more global server load balancing resources see the following: