Horizontal Scaling vs. Vertical Scaling: Choosing the Right One

If the pandemic and our business applications have one thing in common, it’s the difficulty in preparing for the future. Just as we could not foresee the oncome of the virus, we cannot always precisely determine the capacity required to run our applications effectively, no matter how much we plan.

When demand exceeds your application’s ability and capacity to run efficiently, it’s time to scale.

What is vertical vs. horizontal scaling

What is scalability?

Scalability is an application’s ability to increase or decrease overall support and performance in response to the changes in demand. For example, how your company’s website might respond to an increase in visitors is dependent on your application’s scalability. When met with this demand, you want to make sure your application can handle the increase so that it functions properly. Scalability has its limits, and scaling is increasing the capacity of those limits.

The question is: is scaling up or scaling out the right choice for your business?

What is vertical vs. horizontal scaling?

There are two different ways to scale: vertical scaling and horizontal scaling. Vertical scaling, also known as scaling up, is adding more power, or increasing the capacity of a single machine or server for better performance.

For example, you can scale up by adding resources, such as CPU, RAM, or disk capacity to add more processing power to your existing machine. In cloud terms, this translates into increasing the instance type for your application.  In the short term, vertical scaling creates a bigger, better machine for an application to run on. Additionally, vertical scaling is data consistent, as your data is stored on a single node / instance.

One caveat to scaling up, however, is that it comes with limits to the amount of hardware that can be added to a single machine. Vertical scaling also introduces potential for hardware failures. Vertical scaling is easy in the sense that there is no need for as additions only are made to the machine, but is easier better? Not necessarily.

Horizontal scaling, or scaling out, is when you add more machines or servers to your existing pool of resources. In cloud terms, this is referred to as Auto Scaling where the cloud OS can adjust capacity to demand needs. Rather than adding to a single machine as in scaling up, scaling out is duplicating a current set up and breaking it into separate resources.

Instead of changing the capacity of your existing server you are decreasing the load of the server through additional, duplicate servers. More resources might come appear more complex for your business but scaling out pays off in the long run, especially for larger enterprises. Instead of worrying about upgrading hardware as with vertical scaling, horizontal scaling provides a more continuous and seamless upgrading process.

Horizontal vs Vertical Scaling Pros and Cons

Which type of scaling is right for your business?

There are pros and cons to both horizontal and vertical scaling, however, horizontal scaling is currently trending due to its reliability and efficiency. Vertical scaling is simpler, while horizontal scaling may prove to optimize your business operations in the long run. Most commonly, business choose to scale out. Regardless of the environment a business operates in, scaling up requires downtime, which can be inefficient for a business’s operations.

There are a several factors to consider when determining the scaling method right for you:

Flexibility: Horizontal scaling allows for flexibility because you can determine the configuration for your setup that optimizes cost and performance for your business needs. Costs are not optimized when scaling up, as you pay for the set price of the hardware.

Upgrades: With vertical scaling, hardware additions can only be upgraded to a limited extent. Horizontal scaling allows for continuous upgrades since you are not dependent on a single piece of equipment.

Redundancy: Another benefit that comes with horizontal scaling is there is no single point of failure distributed with a cloud environment. If your servers fail, the load balancer redirects the request to a different one of your servicers. Vertical scaling, on the other hand, has a single point of failure meaning if the machine goes down, the application goes down with it. Transitioning to the cloud through horizontal scaling eliminates the potential for this problem.

Cost: While vertical scaling may come with a lower upfront cost compared to horizontal scaling, horizontal scaling optimizes cost over time.

Next Steps

Choosing a scaling method that meets your business needs may seem like a complicated choice, but it does not have to be. 2nd Watch is an AWS Premier Partner, a Microsoft Azure Gold Partner, and a Google Cloud Partner providing professional and managed cloud services to enterprises. Contact Us to take the next step in your cloud journey.

-Tessa Foley, Marketing