Perform your own 30 hour load tests with Kernl!
Over the past 5 months I’ve been writing a lot of different articles testing WordPress performance when under heavy load. One of the comments that I often receive is “Yes, but how reliable is the host over time?”. To determine that answer I made some changes to Kernl that would allow customers to do long duration tests against their providers with a steady load. Given my affinity for Digital Ocean, I figured that would be a great first host to test.
What Was Tested & How I Tested It
Digital Ocean has several data centers across the globe and I figured that I should test each of these data centers to see how reliable they were. For this test I ran a single load test against the following data centers for 30 hours with a 25 concurrent users:
- New York City (NYC3)
- Toronto (TOR1)
- Bangalore (BLR1)
- Frankfurt (FRA1)
- London (LON1)
- Singapore (SGP1)
- Amsterdam (AMS3)
All requests were made from the Digital Ocean data center in San Francisco (SFO2). The target of each load test was a simple $5 / month droplet with the WordPress image from the Digital Ocean marketplace installed on it.
Results
The table below summarizes the results for all of the long duration load tests. Click the region to see more details of the load test.
| Region | Requests | Failures | Failure % | Req/s Avg |
| NYC3 | 2.49M | 139 | 0.005% | 23 |
| TOR1 | 2.46M | 126 | 0.005% | 22/23 |
| BLR1 | 2.17M | 115 | 0.005% | 20 |
| FRA1 | 2.28M | 1405 | 0.06% | 21 |
| LON1 | 2.33M | 1335 | 0.05% | 21 |
| SGP1 | 2.29M | 98 | 0.004% | 21 |
| AMS3 | 2.30M | 228 | 0.009% | 21 |
As you can see from the results above Digital Ocean’s reliability is excellent across the entire testing period. Even the data centers with the highest error rate (Frankfurt, London) had an incredibly small error rate. I’m not going to add the response time distribution results here because they were uniformly excellent.
Anomalies
- The Bangalore (BLR1) test averaged only 20 req / s. Even though the geographic distance is far, I expected the response times to go up but to have a similar throughput.
- The Toronto (TOR1) load test averaged 22 req / s for 28 hours, then jumped up to 23 req / s for that last two hours of the test. Maybe a noisy neighbor went quiet?
- Digital Ocean’s Frankfurt (FRA1) and London (LON1) data centers had an order of magnitude more errors than the other data centers I tested.
Conclusions
As a whole, Digital Ocean performed very well in all of their data centers with a moderate amount of sustained traffic to a WordPress instance. In the future I would like to try running all of these tests twice with a different origin for each test run. It’s also worth noting that I haven’t done this type of test on any other platform yet. I hope that as I test more providers I’ll find out whether or not Digital Ocean performed as well as I think it did.