PHP workers limits, what are your options

Estimated reading time: 4 minutes

There are a couple of ways your site can be running out of resources. One of the common ones we hear a lot about is about a site exceeding PHP worker limits. And we think it’s a little bit silly to be having this problem in the first place. Let me explain.

What are the PHP worker limits at Servebolt?

Let’s start with explaining what a PHP worker is first before I answer this question. PHP, as a programming language is a single-threaded interpreter by design at its core. PHP workers determine how many simultaneous requests a server can execute at a given time. Requests are executing almost instantly.

Questions like “How many PHP workers do I need?” or “What if workers are not enough?” are common questions asked if your site is indeed limited by a fixed amount of workers. At Servebolt, your site is not limited by PHP workers.

Here’s why. The worker limit is something that comes by design from PHP-FPM, the FastCGI Process Manager used by many hosting companies. In our stack we deal with workers dynamically. Meaning that every Apache process is allowed to spin up a PHP process. This means that Servebolt doesn’t limit your PHP workers at all.

Why PHP Worker limits are bad

To have the performance of your site be limited by PHP Workers is not ideal. When your traffic surges and start to run out of workers, the first thing to notice is that requests start queueing. This means your pages will be delivered with delayed responses. The first thing to notice when that happens is higher time to first byte (TTFB).

But it gets worse. If the queue continues to grow, caused by even more traffic, you’ll run into even more issues. Once traffic is just getting too high, that’s when you run into real problems. To the point where pages stop responding at all. Ultimately resulting your site to go down.

What are Servebolt’s limits?

Where our competitors are limiting their PHP workers – at best for their most expensive plans – to 16 PHP workers, we already provide more than that (unlimited) for our entry level Pro plans which start at $99 a month. Having enough processing capacity for PHP or CPU should never be a bottleneck for a website or e-commerce store. That’s why we have the unlimited PHP workers and enough CPU policies.

All our plans scale as you’d expect a scalable platform to do. Learn more about how to calculate how much traffic your site can handle.

But what about PHP memory limit & RAM?

Every single PHP process has access to the maximum amount available as set as PHP memory limit on your Bolt. And you can upgrade it to 1GB if necessary, but that’s rarely needed on our Bolts. This means you never run out of PHP worker limits, but you may be limited by PHP memory limits.

A common bottleneck when scaling a website is RAM. At Servebolt we provide Unlimited RAM for all price plans. This ensures that you don’t need to worry about having enough RAM. Servebolt takes care of that. We make sure your site always has enough RAM available. Servebolt can scale your website more easily out of the box than most other hosting alternatives.

Frequently Asked Questions about PHP Workers

To summarize, these are the frequently asked questions we see a lot about PHP Workers.

What are PHP workers?

PHP, as a programming language, is designed as single-threaded interpreter at its core. Meaning, the single threaded nature of PHP means that PHP doesn’t have any built-in support for spawning new threads during script execution. PHP workers determine how many simultaneous requests a server can execute at a given time.

To put simply: a PHP worker is a background computing process that runs PHP code. It’s ready to process whatever you want it to process on the server, processes what you want to process it and returns the response.

How do PHP workers relate to CPU?

When PHP workers are processing the task that you’ve assigned them, they will use whatever CPU cycles and RAM they have available on the server to perform that task.

How many PHP workers do I need?

The number of PHP workers you need is highly dependent on the amount of dynamic content your website uses. A WooCommerce site, for instance, would need more than a normal blog. Having said that, at Servebolt, you don’t need to worry about the amount of workers you need. Our unlimited CPU policy ensure you’ll always have enough.


So when I said “It’s a little bit silly to be having the problem of exceeding PHP worker limits”, I meant it. We’re in the business of serving you the fastest, most scalable websites possible. It makes no sense whatsoever to limit you in any way while doing so.

If you’re looking for the fastest, most scalable hosting that doesn’t limit your CPU and RAM resources, do reach out to us and we would be happy to set up a copy of your site for testing purposes. You can also create an account directly and set up a copy of your site yourself.

Remkus de Vries

Head of Partner & Customer Relationships

Remkus is Head of Partner & Customer Relationships at Servebolt. He co-founded and lead WordCamp Europe and WordCamp Netherlands. During more than a dozen years he's spoken at many WordCamps and WordPress Meetup groups.

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