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Monday, 7 March 2011

Testing the performance of WordPress on nginx with loadimpact.com


After I set this site live I decided to test the performance of the site under a bit of load, I wanted to check that my thoughts about nginx (and the fcgi cache) were correct.

The results, very promising. For 50 simultaneous users (max for free test) I had ~530ms load time for the homepage. Now I realise this setup of caching can only cache a limited number of pages, but what are the chances of more than a few ever driving a lot of traffic (what is the chance of any of the site!).

So, the full results from loadimpact.com:



As the line is flat, that means the server is not under any stress. So unless I start getting considerably more than 50 simultaneous users, or a large number of popular pages, I have nothing to worry about! All of this scalability relies on the fact that nginx will cache the majority of requests and serve them up instantly, therefore keeping the load off PHP and MySQL.

Although, I have had to tweak the php-fpm config (/etc/php5/fpm/pool.d/www.conf on default  Ubuntu) to lower the number of start and idle servers, as it was eating up the little RAM this server has!

Side note: I have just heard about the Django project which is a Python web-framework. It looks really cool, and would have been really good for some of the internal tools I have written. Hopefully I will find a project soon to play with it on!