GSLB, short for “global server load balancing,” refers to balancing the load among servers distributed worldwide. That way, application servers spread across geographies only process Internet traffic they can manage.

GSLB, in sum, makes it so that no single Domain Name System (DNS) server gets flooded with requests, causing it to overload and stop functioning.

Other interesting terms…

Read More about “GSLB

Before diving into how GSLB works and what it’s for, let’s tackle some essential terms first.

What Terms Are Related to GSLB?

Here are some concepts you need to understand to comprehend GSLB fully.

  • Load balancing: You should know that any computer or server, including DNS servers, can only handle a finite number of requests at one time. If it gets too many requests, therefore, it will malfunction or, worse, stop working as intended, such as when a DNS server suffers a distributed denial-of-service (DDoS) attack. Load balancing prevents that from happening by distributing traffic to multiple computers or servers spread across the globe to process all requests.
  • Application server: A server that processes requests sent to a specific software, solution, service, or platform. It is a type of DNS server that is specifically designed to handle queries meant for a particular program, say, Skype.

Now that you know those terms, we can go into answering “What is GSLB?”

How Does GSLB Work?

The following diagram shows how GSLB works in a nutshell.


When computer users access a web service, their requests are directed to a load balancer. The load balancer decides which application server anywhere in the world is free or has enough capacity to handle the requests then leads them to that server.

What Are the Benefits of GSLB?

Organizations typically employ GSLB to do the following:

  • Improve performance: Ideally, GSLB requires sending requests to the nearest available servers to minimize network latency and issues. By doing that, GSLB enhances website or service performance. Users can thus access sites and use applications faster and without glitches.
  • Customize content: GSLB allows companies to host content on local, tailor-made servers for specific geographic locations and languages. Sites meant for English-speaking visitors are often hosted on servers in countries where most speak the language.
  • Enable quick disaster recovery: Ensuring that applications are always available minimizes the effects of data center or network failures. If servers in Ontario have been affected by a power outage, load balancers will redirect traffic meant for them to servers in Winnipeg, for instance, so requests can still get processed.
  • Make cloud bursting possible: Cloud bursting is the process of sending requests meant for a private cloud server that could overload it to the public cloud. That way, all requests still get processed without causing the private cloud server to malfunction.
  • Ease maintenance: Data center migrations and upgrades can disrupt service availability. But GSLB can lessen or even eradicate downtime by sending requests to servers elsewhere.
  • Ensure compliance: Organizations in some industries like defense, telecommunication, and healthcare must adhere to stricter government regulations. GSLB makes compliance more manageable by using local servers and customizing forwarding preferences to comply with country-specific regulations. Sites meant for audiences with Internet browsing restrictions can be hosted on local servers. That way, the site owners wouldn’t make the mistake of giving them access to prohibited content.

How Can Organizations Employ GSLB?

While companies can rely on open-source GSLB solutions, subscribing to a paid service may be the best option.

Paid GSLB services use a content delivery network or content distribution network (CDN) of geographically distributed proxy servers and data centers. Such services come with administrators and round-the-clock support, easing implementation and maintenance for subscribers. Users thus don’t have to hire additional human resources or train existing personnel to take care of the CDN.

What Should Users Look for in a GSLB Service Provider?

Organizations looking to hire a GSLB service provider should ensure they’re hiring a company that:

  • Has an extensive global network of servers and data centers, ensuring maximum capacity and uptime
  • Distributes application requests based on a site’s health, proximity, geolocation, and response time to ensure a consistent service quality
  • Offers content and language localization to forward requests in specific languages to servers that host customized content
  • Secures traffic and ensures regulatory compliance by applying customized policies based on geolocation information

GSLB, as you’ve seen, is critical for any company that wants to reduce downtime at all costs. It brings various benefits to organizations. But there are specific criteria to consider when looking for the right provider.