Want to load test your own WordPress site? Sign up for Kernl now!
In the world of affordable WordPress hosting there is an array of different VPS providers to choose from. With so many choices how do you know who to choose? In addition to criteria such as ease of use and support, performance is a huge concern for most people deploying WordPress. In this article we’ll take a look at the performance of several different VPS providers in the $5 tier to see how they perform under load by using Kern’s WordPress Load Testing feature.
Who are we testing?
There are a lot of VPS providers out there providing machines in the $5 / month tier, so we’ve chosen 7 of the more popular providers to test against:
- Digital Ocean (1GB RAM, 1vCPU)
- Linode (Nanode 1GB, 1vCPU)
- Vultr (1vCPU, 1GB RAM)
- AWS Lightsail (1 GB RAM, 1 vCPU)
- Hetzner (2vCPU, 4GB RAM)
- Google Cloud (f1-micro: 1vCPU 600MB RAM)
- Azure ($15 A0 1vCPU, 1GB RAM)
What tests will we run?
Using Kernl’s WordPress Load Testing feature we ran 2 different tests per provider:
- No Cache – 200 concurrent users for 30 minutes. We used this test to see raw WordPress performance with no caching enabled.
- Cached with W3 Total Cache + Memcached – 200 concurrent users for 30 minutes. We used this test to see what a more real-world scenario looks like. In general most people use some form of caching on their site.
To make sure that our test setup was consistent across all VPS providers we followed this setup guide, where we ended up with the following versions of software:
With regards to regions, for every test we kept the VPS instances on the east coast of the United States with the exception of Hetzer where we had the VPS instance in Germany.
Results (Request & Failures)
First, let’s take a look at the request / second results across the different providers.
As you can see there is a wide spread of results depending on host. Honestly this wasn’t want I expected when I started. You’ll also notice that the Azure box cost $15/month. It was the closest I could get to finding a $5/month box in their interface (which I felt like I needed another degree in Computer Science to understand!).
So let’s visualize the data with no caching enabled.
We get lots of interesting results here. If you run a site where caching is difficult to do, your $5 will go much further depending on your host. Some notes:
- Google Cloud and Azure performed TERRIBLE. I’m not sure why. Maybe it had to do with accessing the disk so frequently to load up PHP files? (but I expect that those were cached by PHP FPM or some other underlying process).
- If you are in Europe, Hetzner is your friend. $5/month gets you 4x the ram and 2x the vCPUs are the next closest provider.
- If you are in the US, AWS seems to be winning in this test but not by much. It feels like you would be fine going with Digital Ocean or Vultr.
- Before making any real decisions on a host, I’d want to run 5 or so tests across different instances to make sure that there isn’t a lot of variance in my results. Noisy neighbors can often be a problem on VPS providers.
Now let’s take a look at a more realistic scenario where you have a caching plugin installed.
You’ll notice that there aren’t any error bars on this graph. Thats because each host was able to handle the load without having any. This isn’t too surprising since most of the requests would be served right out of memory via Memcached. Some notes on cached requests:
- Once again, Google Cloud and Azure perform the worst out of any of these hosts. Given how highly regarded they are in the hosting ecosystem outside of WordPress I expected better performance.
- All of the other providers posted impressive numbers (170 req/s – 180 req/s). At level I would probably choose whatever provider had the best support, user interface, and reliability.
- I suspect that most of these boxes could handle a little bit more load before going under. If I increased this test by an order of magnitude (200 users to 2000 users) I think most of the providers would tap out before Hetzner does due to how much more RAM and CPU it has.
Results (Response Time Distribution)
While requests per second and failures per second are valuable metrics, in order to get a more holistic view of raw performance for these $5 VPS instances we need to look at response time distribution.
So how should you interpret this chart? For the percentage columns, each value is in milliseconds. If you look at the 99% column, you can see that 99% of Vultr requests returned in <= 3600ms. If you look at the 80% column for Vultr, you can see that 80% of Vultr requests returned in <= 3400ms. Let’s take a look at our un-cached results.
Some notes on this graph:
- Any service that hit the 5000ms mark killed the request. I think that they likely would have gone far beyond that.
- Once again, for $5 Hetzner is just crushing it. You simple can’t compete with 4GB RAM and 2vCPUs. Even with no caching their 99th percentile was under 2 seconds!
- For our non-european readers, Digital Ocean, Vultr, and AWS seemed to perform the best. AWS remained remarkably consistent across the response time distribution range. This is a good thing.
- Google Cloud… wtf? So 99% of your requests finished in <= 5 seconds, and then 90% of requests finished in <= 300ms? Something is fishy.
And now, let’s see how things change when caching is used.
As expected, most providers do very well when caching is used. Digital Ocean, Linode, Vultr, AWS, and Hetzner are all performing in the <= 200ms range (some lower!). It’s hard to decide who is better at this level due to latency due to geographic distance. The point is that you could choose any of those hosts and be OK when using a cache plugin. Once again, I’m struggling to figure out why someone would spend their $5 on Azure or Google Cloud.
Results (Total Requests)
Our final metric we need to look at before we can pass any judgement on our VPS providers is total requests. This in particular needs to be compared with response time distribution.
This graph does a great job explaining some of the discrepancies in the response time distribution data. When caching wasn’t enabled, Google Cloud and Azure barely even show up on the graph. More thoughts:
- I’m 90% positive that the Google Cloud and Azure instances nearly stopped processing requests at some point. They were so overwhelmed that they just fell over. The data seems to support this.
- Google Cloud and Azure are not the best place to spend $5. Even with caching I would be scared if there was ever a cache-miss.
- Hetzner is the clear winner in un-cached data. Once again, this makes sense how much more machine you are getting for your money.
- On the U.S. side of the ocean, AWS seems to win here, although not by much over Digital Ocean and Vultr. Once caching is taken into consideration they all perform roughly the same (accounting for latency between data centers and load generators).
If performance is all you care about for your $5 (and thats a big if), then choose Hetzner if you need a VPS in Europe. If you need a VPS in the US or elsewhere, choose AWS, Digital Ocean, or Vultr. Microsoft and Google are not great for $5.
Want to load test your own WordPress site? Sign up for Kernl now!
Comments are closed.