How can I truly test a performance comparison between two web servers?
I have two dedicated web servers. After my first server has been struggling under load, it is due time for a second server. I purchased a more powerful server for my second server.
Here are the specs:
Dual L5520 Xeon (quad core, 8 cores total, 16 threads)
2.26 GHz, 2.48 GHz max turbo
8 MB SmartCache
5.86 GT/s QPI Bus Speed
24GB RAM DDR3
1TB 5400 RPM Hard Drive
Dual E5-2660 v2 (10-core, 20 cores total, 40 threads)
2.20 GHz, 3.00 GHz max turbo
25 MB SmartCache
8 GT/s QPI
32GB RAM DDR3
Moreover, as can be seen from CPU PassMark, the E5-2660 v2 20-core is nearly 3 times more powerful than the L5520. That makes sense, considering that 20 cores is nearly 3 times more than 8 cores.
PassMark - CPU Mark
Multiple CPU Systems - Updated 9th of August 2017
I tested both servers with the same website using a couple comparisons sites including dareboost and another one I found on google. I also used pingdom although it was unreliable as it changed significantly with every repeat test.
I tested the exact same website which was cloned from one server onto the other, so I was able to view the same exact website on both servers (on server 2 I hosted it as a subdomain).
However, page speed showed only about 3% to 5% improvement with the new server. However, new server is much more powerful as can be seen from the specs. So, page loading speed cannot be an accurate predictor of server power.
For example, it does not take into account how a server would handle heavy load.
Here is the output of the page load speed comparison of the front page of a basic wordpress page with 10 posts on the home page. On the left is the new server. As you see, negligible difference.
For reference, I run a number of wordpress websites, one of which gets around 500,000 views per month. Cumulatively it would probably be millions, I have not counted. I have maybe 20 of my websites running on this server.
I run another website which is not wordpress but gets more views, and has users regularly uploading and downloading files throughout the day every day. It is also on this server.
My first server can handle fine during most times, but during peak load will struggle, and lately the sql usage is very high (hundreds of users on simultaneously uploading/downloading files) and have had to reset sql database and apache just so server would load. Obviously, I have met my limit for server #1. So I plunged into the second dedicated server.
So what I would really like to know is how to really measure how well my new server will be able to handle traffic and how to test to to see how it performs compared to my first server.
What are some ways to test how much better the new server is compared to the old server?