Why a Load Balancer Is Critical to Your Computing System

You might have heard that a load balancer is important in computer software, but like many things in the world of computers, it’s sometimes hard to tell if it’s really necessary. Fortunately, by looking into what a load balancer does and why businesses use it, you can determine if it’s a good investment for you.

What Is a Load Balancer?

A load balancer is quite simply a system that spreads work between multiple servers so that no one server is overwhelmed. For example, imagine ten people go onto a search engine and perform a search. In this case, all the searches would be processed by the same computer unless a load balancer intervened. There would likely not be a noticeable difference in the speed of this simple process, but you might imagine that a single computer would slow down noticeably if several thousand people were sending requests or if the requests were complex. A load balancer simply divides these requests between the available servers so each is processed efficiently.
In the example of an internet search, a software load balancer would be used. There are also hardware load balancers, however. These perform the same sort of function but instead of balancing software applications such as searches or databases, a hardware load balancer is designed to regulate specialized hardware such as switches or routers.

Okay, So, How Does It Work?

Load balancers function based on an algorithm. There are three main algorithms used with load balancers, each with its own pros and cons. Depending on what you want your servers to do, how much traffic comes to your servers, and how capable each of your servers is, one algorithm might work better for you than the others.

  1. Least Connection First Scheduling—this kind of algorithm monitors how busy each server is and sends incoming tasks to the one which is currently least busy. This works well in instances when there are many persistent connections, which require connection with a single server for an extended period of time in order to maintain consistency and synchronization. This type of algorithm might not be the most efficient in an instance where there are many short connections or when a wide variety of devices are attempting to connect to the servers. 
  2. Weighted Scheduling Algorithm—with weighted scheduling, servers are assigned a weight depending on how much work each can handle. The algorithm then analyzes incoming work and sends it to a server that has enough available power to process it. This algorithm works most efficiently when there is a wide variety in the processing power of the servers. Another algorithm might be better if the servers are relatively similar or if the incoming tasks are generally the same size. 
  3. Round Robin Scheduling—as the name implies, this kind of algorithm sends work to servers on a rotation so that each is receiving approximately the same number of tasks. This algorithm is perfect for systems that include servers of fairly uniform capability and generally process short tasks. If the tasks are persistent or might take a long time to complete, the Round Robin Scheduling could get bottled up and might slow down one server while others are idle.

Based on the kind of traffic that comes through your servers, one or another of the scheduling algorithms might work better for you.

Do I Really Need a Load Balancer?

Certainly, there are plenty of applications which do not require a load balancer, but if your servers fit any of the following criteria, a load balancer becomes an essential investment:

  • You have more than one or two servers and you want to make efficient use of all of them
  • You want to have 24/7 server availability
  • One of your servers or computers is being worn down by constant use while others are idle
  • You want to make sure everyone accessing your server can actually communicate with it efficiently
  • You want to expand to world-wide servers
  • You want employees and customers to be able to always receive the same speed of access to your servers
  • You want to save money if one of your servers fails and you don’t want to pay to reroute traffic

These are just a sampling of examples why you might want a load balancer when you control a server. Load balancers overall are inexpensive when compared to the loss you could incur by failing to include one in your systems.