Creating a distributed, scalable WordPress Platform on Amazon Web Services (AWS)

For CloudVane.com we wanted to have a highly scalable, distributed and performing Platform that is also easy to Maintain. These challenges weren’t that easy to achieve and initially we had to find a system.  As CloudVane is all about the Cloud, the solution was easy: it must be a Cloud Provider. We selected Amazon Web Services to server our Magazine.
To better understand the Performance of WordPress, we wanted to have a System that allows us to handle about 8 million hits per day. So we started with a standard WordPress Installation on Ubuntu with MySQL just to figure out what is possible (and what not). We didn’t add any Plugins or so, the first tests were a really plain System.
For the Test, we used Blitz.io, which returns great statistics about the Test run. Our first Test gave us the following results:

• Delay: 477 MS FROM VIRGINIA
• 60 Seconds Test Run with 20 Users per Second at maximum
• Response with 20 Users per Second was about 1 Second

So what does this mean? First of all, we can handle about 20 Users per second. However, the delay of 1 second is not good. Per Day, we would handle about 560,000 hits. So we are still far away from our target of 8 Million Hits per day. The CPU Utilization wasn’t good either – it turned out that our instance takes 100%. So this is the very maximum of an Out-of-the Box WordPress installation. Below you can see some graphics on the Test run.
Test Run #1:
60 Seconds, maximum of 20 Users per Second:

As you can imagine, this simply does not meet our requirements. As a first step, we wanted to achieve better scaling effects for CloudVane.com. Therefore, we started up another Micro Instance with Amazon RDS. On the RDS Instance, we took advantage from the ready-to-use MySQL Database and connected it as the primary database for our WordPress Platform. This gives us better scaling effects since the WordPress instance itself doesn’t store our data anymore. We can now scale out our database and Web frontend(s) independent from each other.
But what about images stored on the Platform? They are still stored on the Web Frontend. This is a though problem! As long as we store our images in the instance, scaling an instance gets really though. So we wanted to find a way to store those instances on Blob Storage. Good to know that Amazon Web Services offers a Service called “Simple Storage Service” or “S3” in short. We integrated this service to replace the default storage system of WordPress. To boost performance, we also added a Content Distribution Network. There is another Service by Amazon Web Services, called “Cloud Front”. With Cloud Front, Content is delivered from various Edge-Locations all over the Globe. This should boost the performance of our Platform.
As a final add-on, we installed “W3 Total Cache” to boost performance by Caching Data. This should also significantly boost our performance. But now lets have a look at the new Load Test, again with Blitz.io. For our Test, we use the maximum we can do with our free tier: 250 concurrent users.
The output was:

• An average of 15ms in delay
• More that 10 million hits per day

Summing this up, it means that we achieved what we wanted: a fully scalable, distributed and performing WordPress platform. It is nice what you can do with a really great architecture and some really easy tweaks. Below are some graphics of our test run.