GuidesBest Load Balancers for 2021

Best Load Balancers for 2021

The best load balancers are able to provide either hardware or software-based load balancing to ensure maximum service availability by offering network traffic distribution services. For example, if your business has a primary business domain, you want your site available to your current customers and your potential customers 100 percent of the time. Comparing the best load balancers (LB) and effectively utilizing their load-balancing capabilities will help provide this level of availability.

In addition to providing simple distributed service to multiple servers, load balancers can help:

  • Prevent denial-of-service attacks
  • Allow legitimate users uninterrupted access to services
  • Protect against single-point of failure outages
  • Prevent traffic bottlenecks to systems

While these hardware load balancer devices have since evolved into what is now called application delivery controllers (ADC), load balancing remains at the heart of an ADC. Enterprises and hosting companies rely on load-balancing and ADC devices to distribute traffic to create highly available services.

How to Choose a Load Balancer

When determining how to choose a load balancer, the first thing to consider is your existing infrastructure. Many load balancing solutions only operate with the vendor’s respective virtual machines (VMs) and resources. So if you’re already operating as an Amazon Web Services (AWS) or Google shop, you will likely want to stick with that vendor’s respective load balancer to avoid a significant overhaul. However, some load balancers are designed to support multiple infrastructures.

Price is also an important consideration. There are many expensive enterprise-grade load balancing solutions. But start-ups and small to medium-sized businesses may be better off opting for free, open-source solutions that have more limited capabilities but are robust enough to serve their specific needs.

Best Load Balancers

Today we’ll highlight a handful of the best load balancers on the market for both hardware and cloud and software-based networks.

F5 BIG-IP Local Traffic Manager (LTM)F5 Logo

The F5 Big-IP Local Traffic Manager (LTM) is part of the BIG-IP product family. This suite of products has a load-balancing solution for almost any budget and application, which can help in the process of cost-comparing load balancers across its product line and against other load balancing vendors.

If you’re already an F5 shop, the good news is you’ll enjoy the same easy web-based administration interface included with other F5 equipment. F5 load balancers can also handle SSL certificates, which removes the pressure from web servers and places it on networking gear where it belongs.

One of F5’s major features is its WAN Optimization Manager, which speeds data transfers over the WAN and enables traffic between data centers to be optimized, encrypted and highly available. This feature makes creating a WAN-based disaster recovery (DR) solution easy and almost automatic.

Azure Load BalancerMicrosoft Azure Logo

The Microsoft Azure Load Balancer is a built-in load balancing solution for internal virtual machines and internet-facing applications. It allows users to build highly-available and scalable web applications and load balance internet and private network traffic. Azure Load Balancer supports TCP/UPD protocols, including HTTP/HTTPS, and SMPT, as well as protocols for real-time voice and video messaging.

There are actually three load balancing solutions provided by Azure:

  • Azure Load Balancer offers highly-scalable layer 4 load balancing by distributing transmission control protocol (TCP) traffic across multiple virtual machines.
  • The Internal Load Balancer allows users to apply internal load balancing for virtual machines connected to the internal cloud service or virtual network.
  • The Traffic Manager balances internet traffic at endpoints based on policies and a set of DNS queries.

Azure Load Balancer also provides reliable security by offering flexible Network Address Translation (NAT) tools to virtualize IP addresses, ultimately decreasing the number of IPs used by an organization. Azure also touts more compliance certifications than any other cloud provider.

Citrix ADCCitrix Logo

Cisco’s exit from the Application Delivery Controller (ADC) and load balancer market has been a boon to Citrix ADC, as the latter has seen significant market share growth following Cisco’s change in ADC strategy. Citrix ADC, formerly NetScaler ADC, frequently competes for the attention of enterprises with F5, with the former’s price/performance value giving Netscaler the nod over F5 in the eyes of many enterprise IT departments.

Citrix also benefits from its platform being the only load-balancing ADC that fully integrates into Cisco’s unified fabric. Using Cisco’s APIC (Application Policy Infrastructure Controller), Citrix ADC automates network provisioning and control based on app requirements and policies for data centers and enterprise environments.

Citrix ADC is often praised for its optimization of application deployment and data center operations, as well as its delivery of network resources in a cloud infrastructure. However, many users report frustration navigating the user interface.

Kemp LoadMasterKemp Technologies Logo

Kemp Technologies holds a significant market share in the load balancing space by offering affordable load balancers for a wide variety of situations, all based on the Kemp LoadMaster. Built on the company’s proprietary software platform, LMOS, Kemp LoadMaster can run on almost any platform. Its load balancer and application delivery controller (ADC) solutions range from the traditional hardware load balancer to virtual load balancers, cloud load balancers and load balancers for bare metal servers.

Kemp also offers a free version of its LoadMaster targeted at providing small companies and developers with Kemp’s robust and proven load balancing and application delivery capabilities. The free LoadMaster solution can be downloaded and run on VMware, Hyper-V, KVM, Xen, Microsoft Azure, VirtualBox, and Amazon Web Services, among other virtualization and cloud platforms.

This free version of LoadMaster is ideal for start-ups and QA/Dev teams with limited resources. The logic behind Kemp’s Free LoadMaster load balancer is that as their customers’ load balancing needs grow and expand, they’ll first look to upgrade to the commercial options from Kemp.

ManageEngine OpManagerManageEngine Logo

While ManageEngine OpManager is a powerful load balancing solution for improving application performance and managing traffic, where it really outshines the competition is with its network monitoring, infrastructure management, and customization capabilities.

ManageEngine OpManager’s real-time and in-depth network monitoring is comprised of over 2,000 performance parameters, allowing users to effectively gauge the health and performance of applications, analyze traffic and monitor the availability of all devices, switches, routers, Ip addresses, and firewalls within a network. All of this information can be viewed through the centralized dashboard.

The OpManager dashboard comes with over 90 widgets so it’s highly configurable to serve an IT team’s specific network management requirements. It also offers rule-based discovery, intelligent alerting, custom notification profiles, and workflow automation to ensure networks are always up and running.

Barracuda Load Balancer ADCBaraccuda Logo

Barracuda Load Balancer ADC offers optimized traffic distribution for application and cloud-based services. But what sets it apart is its integrated intrusion prevention. That’s right, intrusion prevention, not just detection. Prevention means your network remains protected even if you miss a critical patch or update. Barracuda’s update service keeps your system ready to protect you from new threats automatically.

The Barracuda Load Balancer also includes service auto-discovery to ease the pain of initial configuration. Teams can manage your changes, updates and configuration maintenance through the easy-to-use web interface.

The Barracuda Load Balancer ensures high web application performance, availability and scalability, thanks to its server failover feature. Other notable features include global load balancing and content caching.

Resonate Central DispatchResonate Networks Logo

Resonate Central Dispatch is a software-based advanced load balancing solution that uses patented resource-based scheduling technology to orchestrate routing decisions based on actual statistics and heuristics obtained from the server and network data center infrastructure.

As part of Resonate Central Dispatch’s Active Intelligence, lightweight distributed software agents collect detailed information such as CPU load and memory utilization, and combine it with network latency and other metrics to determine the most ideal path for data flow. The result is advanced server load balancing with high availability and optimal performance for all web applications.

Resonate also offers “global server load balancing” with its Global Dispatch offering, a wide area network, global server load balancing software solution that consolidates multiple data centers into a single enterprise-wide resource for disaster recovery and business continuity.

Google Cloud Platform Load BalancingGoogle Cloud Platform Logo

Google Cloud Platform (GCP) Load Balancing allows users to balance traffic across clusters and VM instances on a global scale. Traffic enters Cloud Load Balancing through over 80 global load balancing locations, so organizations can distribute large amounts of traffic in single or multiple regions with high availability.

The curse of your site crashing due to going viral is virtually eliminated with GPC Load Balancing’s seamless autoscaling. This capability allows GCP Load Balancing to automatically scale to handle massive, unexpected spikes in traffic by diverting it to other regions in the world that still have space. There’s no need for pre-warming, so GCP can scale from zero to 100 in a matter of seconds.

Because Google Cloud Platform Load Balancing is built on the same infrastructure as other popular Google apps, such as Gmail and YouTube, you can be sure of its reliability and performance. GCP can support over 1 million queries per second while maintaining high performance and low latency. Google Cloud Platform Load Balancing is a great option for large enterprises that operate globally, as well as those who already use a Google-centric infrastructure.

ZevenetZevenet Logo

Zevenet, previously Zen Load Balancer, is another software-based load balancer. It is available in both a Community Edition and Enterprise Edition. The Community Edition is delivered without any warranty and many of the advanced load balancing features available in the Enterprise Edition, which is fully optimized and developed specifically for use in production environments. Both editions provide support through a distribution list (primarily for the Community Edition) as well as via premium professional support from Zen engineers available on a yearly pricing plan.

Similar to Kemp Technologies, Zevenet enterprise-grade solutions are available in the traditional hardware form factor, as a virtual load balancing appliance, as a cloud load balancer (ZVNcloud) and as a bare metal server appliance.


The NGINX Plus offers integrated load balancing capabilities that provide customers of the NGINX web server with a software-based application delivery platform for efficiently managing and scaling web and mobile applications. It comes at a fraction of the cost of hardware-based solutions in many cases.

The NGINX Plus Load Balancer also offers the flexibility of being easily deployed on-premises on existing hardware or in the cloud. It also provides application-aware health checks and monitoring, with automatic detection and resolution of many issues to significantly improve the availability of web and mobile applications.

NGINX provides a helpful guide for companies considering its load-balancing capabilities that details how the NGINX Plus Load Balancer can be deployed to provide all load balancing for a company, to work in parallel with an existing hardware-based load balancing or application delivery controller (ADC) solution, or to sit behind a legacy hardware-based load balancer or ADC.

In 2019, NGINX was acquired by F5 Networks, so you can expect similar reliability and performance as the F5 Big-IP Local Traffic Manager (LTM).

AWS Elastic Load Balancer (ELB)Amazon Web Services Logo

The final load balancing solution comes from the well-known AWS family – the AWS Elastic Load Balancer. Amazon’s Elastic Load Balancer serves as an ideal solution for enterprises that already have virtual servers running on Amazon’s EC2 cloud service. The virtual load balancing capabilities in Amazon ELB will automatically and intelligently distribute incoming application traffic across multiple Amazon EC2 instances in one or more Availability Zones.

AWS Elastic Load Balancing works with Amazon Virtual Private Cloud (VPC) to provide robust networking and security features, and will automatically scale its request handling capacity to meet the demands of application traffic. Amazon ELB additionally offers integration with Auto Scaling to ensure enterprises have the back-end capacity to meet varying levels of traffic levels without requiring manual intervention.

And for smaller enterprises and those just starting out on AWS, the AWS Free Tier includes 750 hours of Elastic Load Balancing per month for one year and 15GB data processing with Amazon Elastic Load Balancing.

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