Measuring the Performance of WordPress on DigitalOcean Droplets

Earlier this year Kernl launched our WordPress Load Testing offering. Prior to the launch we had been doing a series of blog posts testing the performance of “managed” WordPress providers. In this blog post I’ll test the performance of Digital Ocean’s VPS solutions with a standard LEMP (Linux Nginx MySQL PHP-FPM) installation by scaling it vertically.

Want to measure your own WordPress performance under heavy load? Sign up for Kernl.

Server & WordPress Configuration

The Digital Ocean 1-click LEMP install is already configured to take full advantage of as many cores and as much RAM as is available. During the course of these tests I never needed to tweak any server settings. That doesn’t mean that more performance couldn’t have been extracted through configuration tweaks, but even with these settings we were able to gain useful information about WordPress performance on the different Digital Ocean droplet levels.

With regards to WordPress configuration… there isn’t any. No caching, CDNs, or compression. Just raw WordPress. Its easy to get high performance out of WordPress if you cache everything, but seeing what performance looks like in the worst-case scenario is far more interesting.

The Test

For this series of tests I imported the contents of my personal blog (Re-cycledair) to the target and then used Kernl to run the load tests. Due to the nature of my blog this test is very read heavy. While this isn’t realistic for everyone, for my personal blog the test is representative of the actual traffic that it receives.

The test itself looked like:

  • Concurrent users – 500
  • Ramp up – 2 users per second
  • Duration – 30 minutes
  • Request Rate – Each user makes 1 request every second
  • Droplet location – New York City
  • Load test generator location – Amsterdam

Results

As expected the amount of traffic that we could handle scaled linearly with the amount of hardware we were using (and cost).

Cost -vs- Performance

One interesting thing you’ll see in the graph is that in two places the requests per second actually trend down.

Data

Looking at the data above you can see that I tried Digital Ocean’s standard droplets as well as their CPU optimized droplets. The difference between them is cost and dedicated hyper-threads. From a cost perspective, you’re better off going with the standard droplet in the same price category. Personally I expected the CPU optimized droplet to perform better, but this might not be the best type of workload for it.

What About Caching?

Just for fun I tried out the one-click install of WordPress with LiteSpeed configured on a $5 / month droplet.

Things went really really really well.

🔥🔥🔥🔥🔥

Thats right. By the time the test was completed my little $5 / month droplet was receiving 1800 requests / second WITH NO ERRORS. For perspective, thats 4.6 billion requests per month.

Conclusions

The data does a good job speaking for itself here, but in general you should definitely stick to Digital Ocean’s standard droplets when running WordPress. Even without caching you can get really good performance out of the $40/month droplet.

Want to measure your own WordPress performance under heavy load? Sign up for Kernl.