Scaling Up vs. Scaling Out: What’s the Difference?

Whether you’re running a single WordPress site or a million, you’ve likely come across this question at least once: how do I scale as I grow?

It’s a tough question to face. Should you scale up to a larger server, scale horizontally to additional servers, or is there something else that you should do instead? In this article, we’ll take a look at the different scenarios to help you determine which is best for scaling your site.

Determining Needs

When it comes to scaling WordPress sites, there isn’t a 1-size-fits-all answer. Your business is unique, and your website is no different. Even if your site was built exactly like another, you might not have the same goals in mind. Due to all of these variables, what works for one business may not work for another.

There’s a well-known saying in most industries that you can have it 2 of 3 ways: good, fast, or cheap. It’s no different when it comes to hosting your website. If you’ve kept costs as low as possible and have done the right performance enhancements that your site needs, you might be barely skating by on your server’s resources. What if you wanted the fastest possible site and are willing to spend the money to ensure that nothing ever goes wrong? In many cases, there’s still a performance impact, even if a small one.

So, where do you even start? Let’s take a look at a few things to consider when determining how to scale your WordPress site.


How critical is reliability to you? If your site were to go down for 5 minutes on a Tuesday afternoon, how would it impact your business as a whole? Would you even notice?

In a perfect world, every site would be up and running 24/7. While you might want to guarantee that your website would stay up and running smoothly forever, even in the face of catastrophe, it most certainly wouldn’t be cost-effective or practical. Even the biggest companies in the world, such as Amazon or Google, have issues from time to time. It’s just the nature of the beast.

When determining how to scale your WordPress site, it’s essential to set realistic goals that reflect your needs. If you’re running a local restaurant or any other company that does the overwhelming majority of its business in person, a flawless uptime record might not be your highest priority. In contrast, if you’re operating an online-only eCommerce business, any sort of downtime could be detrimental to your bottom-line.

It’s also important to keep in mind that running a reliable site is much more than how you host it. Things like hardware failures are exceedingly rare, thanks to advances in modern technology. In the overwhelming majority of cases, reliability boils down to how updates are performed, how well your code is written, and a multitude of other factors. When you’re determining your reliability needs, be sure to consider the fact that server reliability can be impacted by far more than server size or quantity when deciding how to scale your site.

When reliability isn’t a critical concern, vertically scaling up to a larger server is usually your best option. It’ll allow you to keep costs lower than having multiple servers and handles future growth by accounting for higher resource usage when traffic grows. The downside is that if that single server goes down, everything else is going down along with it.

If reliability is vital to your business, horizontal scaling is the best option. By scaling out horizontally, you’ll be balancing resources across multiple servers. If a node has an issue, another node is still there to handle your traffic.


We all want our sites to be fast, but how fast is enough? Are you concerned about a few extra milliseconds on the occasional page load?

Perhaps the most important thing to understand about website performance is that it’s not all about the typical “page load time” metric that most people realize. When considering server performance, it’s not about how quickly a page can be served up, but rather how the server handles all of your traffic as a whole. If your site’s traffic increased by 50%, would your page load time remain the same?

Aside from things like a gateway layer to handle horizontal scaling, you’ll need to figure out how your files will be handled. You’ll need to have a process in place to sync data across all of the servers. Not only will it take additional configuration to accomplish, but there can also be increased performance impacts if files or databases need to sync up often.

The performance impact of scaling out to multiple servers can largely depend on your team that’s managing those servers. If you have a configuration that’s highly-optimized for how your site operates, those performance impacts can be minimal.

When determining the best way for you to scale your WordPress site, here’s what you’ll want to consider: If you’re not as concerned with performance as you are reliability or cost, scaling out can be your best option here. On the flip side, if performance is your biggest concern, you may want to opt for scaling up to a larger server.

Of course, if you have the funds to have a great team managing your servers, you’ll likely be able to scale out to multiple servers with a minimal impact on performance.


If you’re scaling your WordPress site, another thing you’ll want to consider is cost. Are you a small startup that’s trying to save money wherever you can? Are you an established business that has a larger budget? How much is your website worth to your business as a whole?

Just like any other business asset, the better your team is, the better your end-results are. Great teams typically cost more, and it’s up to you to determine how much you’re willing to spend. If you have a small group with a lower budget, it might be best to scale up instead of out. As we mentioned earlier, scaling out to additional servers requires more advanced configurations that are custom-tailored to your site based on your needs. Due to these more complex configurations, your team needs more expertise and monitoring capabilities.

Scaling up to a larger server is also a better option if you want “more bang for your buck.” Upgrading an existing server to allocate more resources is almost always cheaper than adding a second server for balancing resources.

Hosting Multiple Sites: Evaluating Blast Radius

Now that you have an understanding of the different things you’ll need to consider when deciding how to scale your WordPress site, let’s look at an additional scenario that might also apply to you: blast radius when hosting multiple sites.

If you’re a WordPress agency who’s also hosting sites for your clients, or even hosting multiple websites for your own business, you’ll want to take further considerations in regards to blast radius. Your site’s blast radius determines how far an issue can reach. Does a problem with one site become an issue for others?

For example, if you have multiple sites and one site decides that it wants to use up all of the available resources or became the target of an attack, it can cause the others to go down as well. If you’re hosting lots of little non-critical sites, some downtime might not be as much of a problem, but if you’re going to get a bunch of phone calls as soon as a client’s website becomes unavailable, you’ll want to limit your blast radius as much as possible.

Scaling horizontally to additional servers is an excellent way to avoid problems with resource spikes. If a site starts spiking in traffic, server resources have a way to spread out. Going even further, if your entire fleet of servers is hitting capacity, you can easily add additional servers to handle the load relatively quickly.

Beyond Hardware

If you’re increasing in resource usage, you might not even need to add more hardware. Often, it’s something as simple as optimizing your WordPress site or server.

Making sure that your code runs as smoothly as possible is a great start. By understanding your site’s performance as a whole, you’ll be able to make better decisions that could save you quite a bit of that hard-earned money. Even if you don’t have a dedicated development team working on your site, hiring a good freelance developer or agency to perform a few performance enhancements can save you a ton of money in the long run.

Having an experienced team to manage your servers can also have an astronomical impact. An elite group of talented people can identify those opportunities and provide creative solutions to squeeze even more performance out of your existing setup. Frequently, these enhancements have a minimum impact on your budget, if any impact at all.

So How Should I Scale My WordPress Site?

Every site is unique, and there isn’t a simple answer to how to scale every WordPress site. It’s all going to depend on what’s essential to your business. Are you looking for more performance? Better reliability? The cheapest possible route to handle growth?

If you’re looking for better reliability, your best option is usually to add more servers and scale horizontally. When trying to get the most out of your investment, scaling vertically to a larger server is going to be your best option. If you need increased performance, you’ll want to take a look at how your code is performing (and if all else fails, jump to a bigger server).

Of course, these are all general rules. Determining how to scale your site is much more complicated than what could be written in an article or even an entire book. 

The complexities involved with scaling WordPress sites are best handled by always having an experienced team in your corner. If you’re not an expert in scaling sites, your best asset is someone who fully understands how your website runs and can provide deep insight on how to grow it.

Need a team of WordPress experts to have your back? Pagely is always here to help your business grow.

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