Scaling-out WordPress – Performance Measures – APC influence of the fronts

APC Influence overview

Results overview

In this post, I’m going to evaluate what increase of performance we could expect from using APC (Alternative PHP Cache).
APC is a opcode cache. That means that with APC, the PHP executable that is embedded in each apache process does not have to compile in opcode each PHP script.
The opcode is compiled during the first execution and is maintained in a shared memory area, so the successive php executions can get directly the opcode from the memory for each new request. In theory, we gain the time to compile from PHP script to opcode for each successive request.
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Scaling-out WordPress – Introduction

This post is the first one of a series about scaling out WordPress.


The purpose of this series of posts can be summarized as followed:

  • Experiment the different bricks (load-balancer haproxy, mysql replica, session sharing)
  • What kind of performance increase we can expect ? Is the performance increase linear with the number of web fronts?
  • What will be the bottlenecks ?
  • What kind of tools can we easily use to stress the application ?
  • What kind of tools can we easily use to measure the performance metrics  ?


Software installation
Performance Measures

to come :
Sessions sharing
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