Clustering and load balancing are technical terms used to describe the backend functioning of hosting applications. They are terms that networking technicians will use when explaining the functionality and performance of a server. The terms are sometimes used interchangeably when in fact they actually refer to different types of applications. In order to compare the two, it is important to first understand each term and how it is used in the industry.

Defining Clustering

Clustering is comparatively the simpler of the two applications. It also refers to computer software rather than hardware.  The process of clustering refers to the conversion of a single function of an application to a master controller. From there, the requests are then sent to multiple functions. For example, on an e-commerce site, clustering may be used when a customer has items in a shopping cart. When they capture the payment details, the process needs to then close the transaction and take the customer to a new page to show that the transaction is complete. The clustering is done using standard industry algorithms. Because there are several processes that need to happen almost simultaneously, clustering provides a way to improve the response time of a server or increase its capacity. It does this by adding further functions to the servers. Because of the feature, clustering is often confused with load balancing in that load balancing has a similar capability.

What Is Load Balancing?

Load balancing often refers to Application Delivery Controllers, more commonly referred to as ADCs.  As mentioned, load balancing also increases the capability and capacity of hosting servers. However, the main difference is that compared to clustering, load balancing uses more complex algorithms. Because of this, they have the faster response times of the two as well as greater functionality and flexibility. Where clustering can only use traditional application variables, load balancing has the capability to draw information from other sources such as network-based data. Load balancing is also more transparent than clustering.

The Pros and Cons of Clustering

A big advantage of clustering is that it doesn’t require highly advanced technical knowledge in order to implement. Someone with a basic level of networking knowledge will be able to set it up. Clustering applications usually come as part of a server enterprise package and because of this, they are considerably cheaper. On the down side, major disadvantages of clustering are the limitations it has. You can generally only use clustering on homogeneous servers and even then high availability is not guaranteed. Most clustering applications also use separate hardware for the cluster controller. Because of this, on managed application sever instances, node agents are needed. 

Comparing ADC Load Balancing

In general, ADC load balancing applications are reputed to provide higher availability and better load balancing. In addition, it can do this in less restrictive homogeneous environments. Technicians like them because when they are deployed there is no need to make changes to existing servers or applications. Perhaps the biggest advantages are that load balancing provides better server performance and improved server security; it also has the added value of optimizing the applications. The disadvantage to ADC or load balancing is that it requires more advanced technical networking knowledge to set up and manage. If you do not have employees capable of managing the process, you may need to bring in outside expertise or train employees to become competent This can be both time-consuming and expensive. ADC also requires additional infrastructure to be built into the architecture of the server which complicates the management of it. The last con is that these solutions are generally more expensive than clustering.

How Do You Choose Which Option Is Best for You?

The decision on whether to use clustering or ADC load balancing is one that you should take your time making. It is a complex issue that has many variables. Firstly, consider the technical expertise that you have at your disposal and if the skilled individuals are more proficient in either clustering or load balancing. Sometimes you may not be able to justify the additional expense of getting the necessary technical skills. Cost is another important consideration. You need to look at this in terms of the set up as well as the ongoing maintenance costs. Perhaps most important though is how important server performance is to you. When you look at the results that you want and what this could mean in terms of customer satisfaction and retention, then it may well be worth your while to spend the money on more advanced technology.