What is Load Balancing? Should you really consider it?

What is Load Balancing? And should you really consider it? 

Connectivity speed has never been so important. Whatever the size of your organization, you need a fast network and stable performance. Any issue can mean loss of sales and customer dissatisfaction. This is where load balancing comes into play. It helps you have better distribution and a sustainable network. 

Load balancing has been around for a long time. Initially, it was placed between end devices and application servers, but it has evolved and now is not just a simple distribution method. There are load balancers with different purposes – for applications, between servers, or many routes to one. The load balancer can have many additional features like traffic health checks, extra security, and better availability. 

If you think: “How the heck is this the first time I’m hearing about it? What is load balancing? Should I really consider it?”. Perhaps your business is not yet there. Be ready for that big moment! Let’s explore together load balancing specifics! 

 What is load balancing? 

Load balancing, or DNS load balancing, is distributing network or application traffic across multiple servers to ensure no single server becomes overwhelmed with too many DNS requests. By doing this, DNS load balancing improves the overall performance, reliability, and availability of applications and websites. 

Learn more about DNS. 

 How does load balancing work? 

DNS load balancing can be achieved in different ways based on the type of load balancer you implement. Generally speaking, load balancers manage incoming client requests in real-time and direct them to the most suitable backend servers. To avoid overloading any single server, the load balancer distributes DNS requests across multiple available servers, whether in cloud data centers, server farms, or on-premises.  

Let’s understand that a suitable backend is a “healthy” one. Load balancers can monitor the pool of available backend servers, so they only forward traffic to healthy ones. Those checks involve connecting to backend servers through a specific port and protocol to ensure that communication is possible. If a backend server does not answer, it means it can’t respond to DNS requests so it is discarded.  

When a server receives a request, it processes it and sends the response back through the load balancer. The load balancer then establishes the connection between the server and the client by aligning their IP addresses allowing them to communicate and complete tasks throughout the session. 

During high-traffic periods, a load balancer can activate additional servers to handle the increased demand. Conversely, during low-traffic times, it can scale down the number of active servers. Load balancers also facilitate network caching by directing traffic to cache servers that store previous user requests temporarily. 

 What type of traffic can load balancers manage? 

HTTP 

This standard HTTP load balancing directs DNS requests using standard HTTP protocols. The load balancer updates headers such as X-Forwarded-Port, X-Forwarded-Proto, and X-Forwarded-For to provide backend servers with information about the original DNS request. 

HTTPS 

HTTPS load balancing operates similarly to HTTP but includes encryption. Encryption can be managed in two ways: SSL passthrough, which maintains encryption from client to backend, or SSL termination, where the load balancer decrypts the traffic before sending it unencrypted to the backend. 

TCP 

Not all applications use HTTP or HTTPS. Some use TCP traffic and it also can be balanced. For instance, traffic directed to a database cluster can be distributed across multiple servers. 

UDP 

Currently, some load balancers have begun supporting core Internet protocols that use UDP, such as Syslog and DNS, allowing these protocols to also benefit from load balancing. 

Benefits of load balancing 

Enhanced Security 

Load balancers can add an extra layer of security by hiding the backend server’s IP addresses, protecting them from direct attacks. They can also enforce SSL/TLS encryption and manage security certificates. It can also help against DDoS attacks.  

Scalability 

Load balancers enable horizontal scaling by distributing traffic among multiple servers. As demand increases, additional servers can be added to handle the load, ensuring the application can scale efficiently. 

Reduced Latency and Improved Performance 

Load balancing distributes incoming traffic across multiple servers, ensuring no single server becomes overwhelmed. This improves response times and reduces latency, providing a better user experience. 

High Availability and Reliability 

By balancing the load among several servers, load balancers help applications to remain available even if one or more servers fail. They can detect unhealthy servers and redirect traffic to healthy ones, minimizing downtime. 

Efficient Resource Utilization 

By distributing traffic evenly, load balancers ensure optimal utilization of server resources. They prevent servers from becoming a bottleneck or being underutilized. 

 Session Persistence 

Load balancers maintain session persistence, ensuring that a user’s session is directed to the same server throughout their interaction. This is crucial for applications where user sessions need to be maintained. Think about e-shops which require all requests from a single client get directed to the same server throughout a session – from the moment this user adds items to a shopping cart, until they complete the purchase. Session persistence ensures a continuous connection between the client and the server. Without it, data would need to be synchronized across multiple servers, potentially causing delays and reducing performance efficiency. 

Fault Tolerance 

Load balancers contribute to fault tolerance by rerouting traffic from failed servers to healthy ones. This ensures continuous operation and helps maintain service availability during server failures. 

 Traffic Management and Analytics 

Load balancers provide valuable insights into traffic patterns and server performance. This data can be used to optimize resource allocation, detect anomalies, and plan for future growth. 

 Simplified Maintenance 

With load balancing, individual servers can be taken offline for maintenance without affecting the overall availability of the application. Traffic is simply redirected to other servers, allowing for seamless updates and maintenance. 

Geographical Distribution 

Load balancers can direct traffic to servers located in different geographic regions, reducing latency for users by routing them to the nearest server. This improves performance and user experience for global applications. 

Cost Efficiency 

By optimizing resource use and enabling efficient scaling, load balancers can reduce the need for over-provisioning, leading to cost savings on infrastructure. 

Now you see it clearer! DNS load balancing is a critical component for ensuring that modern applications are fast, reliable, and scalable, enhancing operational efficiency and user experience. 

Load Balancing Algorithms 

Load balancing algorithms determine how incoming traffic is distributed across multiple servers to ensure optimal resource use, maximize throughput, and minimize response times. Here you have some commonly used load balancing algorithms: 

Round Robin 

This load balancing algorithm distributes requests sequentially among all available servers. It follows a circular order to distribute DNS requests. If you have three servers, Round Robin will send the first request to the A server, the second request to the B server, the third request to the C server, the fourth request to the A server, and so on. It is a simple and effective solution for environments where servers have similar capabilities and the load is relatively uniform. 

Weighted Round Robin 

Similar to Round Robin, but it works by assigning a weight to each server based on its capacity. Servers with higher weights receive more requests. The administrator, who knows every server’s capacity assigns the weight for the load balancer to work accordingly. It is a useful choice when servers have different processing powers and general capacities.  

Least Connections 

It directs traffic to the server with the fewest active connections. This algorithm accounts for the different workloads of servers. Ideal for environments where the load can vary significantly over time, ensuring that no single server becomes a bottleneck. 

Weighted Least Connections 

It works like the least connections algorithm but considers a second factor, server weights to distribute connections more effectively. It is a helpful choice in heterogeneous environments where servers have different capabilities thanks that it accounts for both active connections and server capacities. 

IP Hash 

Uses the client’s IP address to determine which server will handle the request. The same IP address will always be directed to the same server. This algorithm is essential for businesses requiring session persistence. It ensures it (session persistence) without needing cookies or other tracking mechanisms. 

Least Response Time 

It is a load balancing algorithm that sends traffic to the server with the lowest response time and the least number of active connections. It prioritizes faster-performing servers. It is a solution for improving overall application responsiveness and performance. 

Least Bandwidth 

This load balancing algorithm routes traffic to the server currently serving the least amount of traffic in terms of bandwidth. The choice for scenarios where bandwidth consumption is a critical factor. 

Resource-Based 

It distributes the traffic taking into account various server resources such as CPU and memory usage. 

Ideal for environments with varying resource loads and applications that are resource-intensive. 

Random 

This load balancing algorithm distributes traffic randomly across all available servers. Simple and effective in specific scenarios, but not commonly used due to its lack of efficiency in load distribution. 

Adaptive Load Balancing 

It dynamically adjusts the distribution of traffic based on real-time analysis of server performance and traffic patterns. Suitable for highly dynamic environments where traffic and server performance can fluctuate frequently. 

Geographic Boad balancing 

The algorithm routes traffic based on the geographical location of the client and the servers. 

Helpful for global applications to reduce latency by directing users to the nearest server. 

Content-based 

It distributes traffic based on the content of the request, such as URL, cookies, or application data. 

It is beneficial for applications that serve different types of content that may have different processing requirements. 

Each algorithm has its strengths and suits specific scenarios. Choosing the right load balancing algorithm depends on the nature of the traffic, the server infrastructure, and the specific requirements of your online business or application. 

Types of load balancers 

You have to analyze your business needs to choose the right load balancing method. You want availability 100% of the time, right? 

Physical Load Balancer 

A physical or hardware load balancer is an actual physical device designed to manage workloads. It is a more expensive option because you will need to buy both the hardware and the software for it. Still, it is a very common load balancer. It is located right after the firewall and before the server/s. In it, the firewall, cache server, SSL accelerators, all-in-one gatekeeper, and ADCs can be included. 

Virtual Load Balancer 

Virtual or software load balancers run on a virtual machine. The software manages the traffic. It is cheaper and can work on different hardware. The problem with this one is that the updates can mean downtime. 

Cloud-Based Load Balancer 

Cloud platforms provide such a load balancer. It has a wide variety of functionalities like interruptions management, failover, network issues diagnostics, and traffic distributions. It is fast and dramatically reduces the load on applications. It is secure. It can stop different types of DDoS attacks. You can choose different prices depending on your needs and easily upgrade if you need more. 

A cloud-based loading balancer can have GEO DNS. It checks the IP addresses of the customers and redirects them to the closest server. You can create a whole CDN with it and provide excellent speed and reliability. 

What types of online businesses can benefit from load balancing? 

All of them! Seriously, each website with high traffic, e-commerce platforms, online retailers, cloud service providers, gaming industry, large enterprises, content delivery networks (CDNs), healthcare and telecommunications, Internet service providers (ISPs), government and educational institutions. 

All modern applications with a daily need to manage millions of simultaneous sessions and deliver the appropriate videos, images, text, and other data to each user swiftly and reliably, can benefit from load balancing.  

Conclusion 

Now, you know what load balancing is! And yes, you should consider the implementation of this technology. Let’s say load balancing is a must-have for every medium and large business. 100% uptime and extra protection will give you a competitive edge over your competition. Load balancing is the easiest way to forget about downtime and slow website loading. 

We trust that your traffic, just as your success, will grow enormously soon! So, load balancing will become essential!