As you approach Black Friday Cyber Monday (BFCM)—or any time of the year when your online business experiences a spike in sales—it’s imperative that your website can handle the increase in traffic. 

In 2020, eCommerce sales during BFCM soared, with a 74% increase in gross merchandise volume (GMV) year over year (YoY). As an online merchant, this is your time to shine. However if users run into responsiveness issues while shopping on your site, you’ll likely miss out on sales and conversion opportunities. 

With effective load balancing, you can ensure that your website won’t slow down or crash during times of increased demand. In this article, we’ll discuss the ins and outs of load balancing, from the different types available to the various advantages they provide for eCommerce businesses. 

What is load balancing and how does it work?

Load balancing refers to the efficient distribution of network traffic across multiple servers. This is accomplished using a load balancer, which manages the flow of data between web servers and user devices like laptops, smartphones, and tablets. 

When a user initiates a request on a site, the load balancer determines which web server should handle the incoming request—based on a variety of algorithms. Load balance algorithms fall into these two categories:

• Static load balancing algorithms distribute workloads to servers based on a predefined set of rules. These algorithms are quick to deploy but can come with inefficiencies. 
• Dynamic load balancing algorithms take several factors into account before assigning workloads to servers. This includes overall server health and the unique capacity requirements for individual tasks. Since dynamic algorithms are more methodical, they tend to be more efficient, but also more difficult to configure. 

Here’s a helpful analogy: Let’s say you manage a grocery store with five cashiers working at once. Each cashier represents a different server, with the line of customers representing the server load. To speed up the checkout process, you hire a new employee—who represents a static load balancer—to direct the traffic of shoppers so that each cashier handles the same amount of transactions. But what if some of your cashiers take significantly longer to scan items and process customer payments? This will lead to longer customer wait times, as well as job burnout and decreased productivity among the cashiers. Employing a detail-oriented coordinator to direct shopping traffic—while keeping in mind individual cashier speed and other relevant factors—represents utilizing a dynamic load balancer. 

Through server monitoring, dynamic load balancers perform regular health checks to make sure servers are operating correctly. If a server is running slowly, then the load balancer will reroute some of that server’s traffic to another server or group of servers. 

In cases where the server has shut down completely, the load balancer will automatically redirect that traffic to functioning servers. This is a process called “failover,” and it’s crucial for any online store that experiences a high volume of network traffic. Without a backup in place, a crashed server will render your site or application inaccessible. And depending on how long it takes to get the server back up and running, this can end up costing your business thousands of dollars in revenue. 

Load balancing typically works on layers four and seven of the open systems interconnection (OSI) model:

• Layer four (L4) load balancers make routing decisions based on data sourced from network and transport layer protocols. In other words, they work on the transport level, looking at the destination IP address for each packet—or “chunk” of data—then sending it to its intended location. 
• Layer seven (L7) load balancers work on the application level, offering a more computationally intensive method for distributing network traffic. Before sending requests to servers, the L7 load balancer pulls data from a packet—such as HTTPS headers and cookies—to gain a better understanding of the client request. This allows for a more structured routing of traffic across networks. 

With proper load balancing, you can prevent server overloads, keep your site from breaking or slowing down, and ultimately facilitate a smoother customer experience. This becomes especially important during peak sales seasons when eCommerce sites create extra work for their servers by generating more user traffic, engagement, and sales.

A brief history of load balancing

In the 1990s, organizations started implementing hardware appliances to distribute traffic across networks. Through application delivery controllers (ADCs)—or computer network devices housed in datacenters—businesses could improve the accessibility of applications run on servers. Eventually, ADCs began offering application services beyond load balancing, such as caching, compression, and application layer security. 

As digital technology advances and businesses require more from their servers, the definition of load balancing has evolved to encompass more than just managing network traffic. Modern load balancers are used to conduct frequent health checks on servers, remove unhealthy servers from networks, improve website security, and provide detailed traffic analytics. 

Hardware- vs software-based load balancing

Today, load balancers can be powered by either hardware or software. With a hardware-based solution, your proprietary software is loaded onto a server, which is usually located in a data center. As your business grows and your site starts taking on more traffic, you’ll need to purchase additional server load space from the data center. 

Software-based solutions tend to be more flexible and less expensive, as they eliminate the need for a physical machine. With this approach, you can install your load balancing software in cloud environments like Amazon Web Services (AWS). You can also use elastic load balancing (ELB), a load balancing service created by Amazon specifically for AWS users.  

Here are some more factors to consider when choosing between hardware- or software-based load balancing:

• Hardware appliances typically come with a large fixed cost, while software requires ongoing costs for upgrades. Though, you may need to pay a team of experts to configure and maintain the appliance for you. 
• A software load balancer offers better scalability, as you can add more software instances to the cloud as you need them, without having to purchase and maintain additional servers. 
• A hardware load balancer may offer greater security since only the organization has access to the physical servers.  

Signs of a good load balancer

Since every website has different needs, there’s no one-size-fits-all load balancing solution. However, there are two important qualities shared among modern load balancers that every business should keep in mind: Session persistence and dynamic configuration.

Session persistence

Good load balancers are programmed to keep individual user information on a single server load, throughout the entirety of that user’s site interactions. For instance, let’s say a customer’s browsing history from one session is stored on an upstream server to create a more personalized experience during their next site visit. If the load balancer switches to another server for the user’s second session, it will then have to fetch the browsing history from the first server. Inefficiencies like these can have a negative impact on site performance. 

Dynamic configuration

Many modern load balancers have the power and intelligence to add or remove servers without disrupting site performance. In cloud environments like AWS, merchants can just pay for the computing capacity they end up using. So when network traffic spikes, the load balancer automatically brings on new servers. And when traffic goes down, they can unemploy those servers to save costs. 

Load balancing algorithms 

Again, choosing the right load balancing solution will depend on your site’s specific needs. This is why load balancing is broken up into several algorithms, each with its own benefits:

• Round Robin: This algorithm is based on a rotating list of servers. Workloads are assigned sequentially. So when a server takes on a request, the next request will go to the next server in line, regardless of how big or small the task is. The problem with this method is that it can cause one server to take on significantly more work than the others, potentially leading to an overload. 
• Least Connection: Unlike the Round Robin, this algorithm sends requests to whichever server has the lowest number of active connections, or the smallest workload. 
• Least Time: A slightly more sophisticated approach, the Least Time algorithm sends requests to whichever server has both the fewest active connections and the fastest response time. 
• Hash: With this method, requests are routed based on key data inside the packet, such as domain name, IP address, and port number. 
• Random with Two Choices: Used in conjunction with the Least Connections method, this algorithm picks two random servers, then sends the request to whichever one has the fewest number of connections. 

Now that we understand the different types of load balancers, let’s get into the primary benefits of a modern load balancing solution.

Benefits of load balancing

To unlock the full potential of your company’s BFCM performance, a classic load balancer might not be good enough. You’ll need a solution that can not only handle the spike in traffic but also support other important business functions. Sophisticated load balancing solutions offer the following advantages to eCommerce merchants:

• Efficiency: By streamlining the process of distributing incoming network traffic, you can spend more time and resources on building the ideal customer experience. 
• Predictive analytics: Modern load balancers can predict increases in network traffic before they occur. This allows you to avoid bottlenecks and system overloads that could compromise your site’s performance. 
• Security: In addition to regular user traffic, load balancers can optimally reroute hacker traffic as well. Cyberattacks, like a distributed denial of service (DDoS), can be offloaded from corporate to public servers, protecting the sensitive data of your business and its customers. Also, load balancers can encrypt all HTTPS data so it’s not vulnerable to hackers while traversing the network. 
• Scalability: As discussed, proper load balancing allows your business to cost-effectively scale up as demand increases. Dynamic load balancers can intuitively add new servers to your network when traffic spikes. Without the looming threat of poor responsiveness or site outages, you can comfortably implement new apps, service more customers, and grow your business. 

Prepare for peak sales season by investing in load balancing

Before the next BFCM, it’s essential to check your current load balancer and make any necessary upgrades. If your website is using a static load balancer, you might experience performance issues as more customers interact with the site, which can lead to lost sales and conversion opportunities. Don’t let your legacy load balancer hold your business back. 

Here at Codal, we recommend using a state-of-the-art eCommerce platform like BigCommerce or Shopify to power your site, since they are equipped to handle sophisticated load balancing. As a trusted partner to both BigCommerce and Shopify, we can assist in migrating your site to one of these platforms. 

Like we’ve done with many clients in the past, we’ll guide your company through the process of preparing for BFCM, so you can reach your sales goals and expand your customer base. Our solutions come with a team of expert designers, engineers, and testers who will help build the most optimal customer experience for your brand. 

Interested in learning more about load balancing and how to prepare your online business for BFCM? Get in touch with Codal today!