Load Balancer: what is it and what is its importance?

When a given system is heavily accessed, it is recommended to invest in a load balancer.

This solves the problem of slowness caused by system overload as it distributes traffic among different web servers in the resource pool. Thus, you can optimize its performance and significantly reduce its response time.

In this article, we bring more details about this solution, which can be applied in hardware and software, alone or together. Our text is divided into items to make it easier for you to understand the subject. These are:

• What is a Load Balancer and How Does it Work?
• Benefits of a Load Balancer
• Brief History of the Load Balancers
• Load Balancing and Cloud Environments
• Load Balancing Algorithms
• Other Load Balancing Algorithms
• Situations where Load Balancing is Essential

Enjoy it!

• What is a Load Balancer and How Does it Work?

As mentioned in the introduction, a load balancer is intended to distribute traffic to different web servers in the resource pool. This way, it ensures no server is overloaded. 

The consequence is the reduction of the server’s response time, which starts to work with maximum performance. 

This is because this solution has the function of routing requests to the right places, providing performance and security for complex IT environments and the operations developed through them.

Let’s suppose you have three computers, but only two are operating, while the third is idle. In this case, load balancing will redistribute the workload between the equipment in order to ensure efficiency in their deliveries.

• Benefits of a Load Balancer

Using a load balancer is very beneficial for several reasons. Check out its main benefits:

• It increases efficiency: When you have a heavy workload, your network slows down. With load balancing, you can distribute it on more than one computer and/or server, increasing efficiency.
• It allows you to manage the traffic flow: Many companies deal with a large volume of traffic in their daily activities. This traffic must be managed in such a way as not to overload the system and maintain the speed of operations. A load balancer helps manage traffic by distributing the workload across multiple computers or servers. 
• It upgrades without downtime: With load balancing, networks gain more flexibility. The redundancy inherent in this solution makes it possible to transfer the workload to a defined server or server cluster for the others to be updated. Thus, these updates will not affect data access and operations.
• It eliminates system failures: A load balancer also helps prevent network failures, which can occur as a result of failures in a server cluster. 

When configuring or updating your network, you should create server clusters using the same application. In this way, you can remove a failed server from your system easily. What’s more, the load balancer also allows you to transfer the workload to a functioning server without causing problems.

• Brief History of the Load Balancers

This concept was created in 1990, with the proposal to enable the distribution of traffic in networks through specific hardware.

Subsequently, the development of Application Delivery Controllers (ADCs) provided more security to the load balancer, as new ways were sought to guarantee access to applications without interruptions and at any time.

ADCs can be: Hardware Appliance, Virtual Appliance, and Software Native Load Balancers. Today, ADCs created from software have the function of performing operations as hardware would and in a more scalable, functional, and flexible way.

• Load Balancing and Cloud Environments

Large workloads in cloud environments can overload a single server. For this reason, load balancing is ideal for ensuring operations are performed efficiently in this context.

Another important function of a load balancer is to ensure the scalability of a cloud: This is what provides more speed for servers and the execution of various applications through the distribution of traffic.

With load balancing, servers receive inbound traffic in a coordinated fashion. Thus, it is possible to avoid that some servers are overloaded while others are with zero traffic.

Moreover, a load balancer makes it possible to identify unavailable servers to direct traffic to those that are operating. That way, you can have infrastructures in different places, as long as you sign up with a cloud service provider.

This is critical as regions can experience natural disasters and become inoperable. In this case, traffic is directed to another region, which has not been impacted by the catastrophe.

A load balancer can also determine which server is likely to be overloaded in the least amount of time and share the traffic with others. This capability reduces the possibility of service becoming unavailable.

The more demands an organization has, the greater will be the traffic of employees, suppliers, partners, and clients. 

As such, your cloud infrastructure must be able to support this load without becoming unavailable or reducing its responsiveness. That is the purpose of load balancing.

• Load Balancing Algorithms

Load distribution is performed using an algorithm. This means the user has access to the websites using a URL associated with an IP and the load balancer, which directs the request to the server. 

Load sharing is directly related to the type of algorithm used, and the four most known are:

• Round Robin: This is a method capable of placing incoming requests in a queue. With load balancer management, one can distribute these requests to servers, responding to them according to the availability of computers.

This solution is adaptable to locations where the servers have the same features. On the other hand, the algorithm can assign overload to less powerful equipment.

• Weighted Round Robin: 

Unlike traditional Round Robin, it works according to the capacity of each server, which is pre-set with a value. It works like this: While the most powerful can have a value of 10, it is possible to assign the least powerful a value of 1. 

With that, the most powerful equipment will receive the greatest load. Therefore, this method is more recommended for use with different servers.

• Least Connections

Round Robin and Weighted Round Robin do not work taking the number of connections the servers will handle into account. Thus, some servers can be overloaded, when receiving a backlog of connections. 

This problem is easily solved by Least Connections, which works considering the requests that already exist on the server when distributing new ones. 

However, this algorithm may not work depending on the technical capabilities of the servers. For this reason, it is recommended to be used in environments whose servers have the same features. 

• Weighted Least Connections

This algorithm works as a complement to Least Connections. In an infrastructure whose servers have different resources, it considers the requests for each piece of equipment, in addition to the weighting established by the administrator.

As with Weighted Round Robin, the most powerful server has the most weight. With this, one can distribute the load strategically, as new requests are directed to a server with the lowest assets/weight.

• Other Load Balancing Algorithms

In addition to the four best-known load balancing algorithms presented in the previous topic, other types perform load balancing. Check some methods below:

• Lower Bandwidth Algorithm: In this case, traffic is measured in Mbps. Thus, it is possible to send requests to servers with a smaller number of Mbps of traffic.
• URL Hashing: This algorithm is capable of evenly distributing writes across multiple websites and directing reads to a specific website.
• Resource-based Algorithm (Adaptive SDN): This method involves knowledge of all application layers and the inputs of an SDN controller, which determines decisions regarding traffic distribution.
• Resource-based Algorithm: Here, a computer program is installed on the server so that it provides the current load for balancing. This is possible based on an assessment of the servers and the availability of resources that allow traffic to be properly directed.
• Source IP Hashing: It mixes client and server IP addresses, creating a unique hash key, capable of allocating traffic to certain servers.
• Situations where Load Balancing is Essential

To understand the importance of investing in load balancing, it is worth looking at the cost-effectiveness of this investment. In other words, how much it costs to have this service and how much your business can lose without correct load distribution.

If you have an e-commerce business operating during periods such as Black Friday, Christmas, Mother’s Day, Valentine’s Day, or other important dates for commerce, for example, the load balancer can avoid major losses.

In this article, we discussed what a load balancer is, its benefits, and its importance for companies. If our content was helpful to you, please share it with more people who might be interested in the subject.