It’s easy to see that using server side caching and careful server configuration gives excellent results. What using a content delivery network means is that the delivery of content will grow more consistently. One problem with many servers, and one which is rarely acknowledged, is the performance available from the network interface. Most won’t serve more than 100mb/s in theory, and about 70mb/s. What can’t be seen in the charts is the momentary output peaks of over 130mb/s that we saw using the content delivery network. The charts just show the averages. As a consequence it’s hard to show the improvement gained from using a CDN at the 1000 user level.
I’m sure most of you know but I’ll just cover it quickly for those that don’t. Each time a PHP web page is requested the web server has to compile the human readable PHP code into a language the processor can understand, this is called opcode. APC will cache opcode in RAM so that subsequent requests for that file do not have to go through that same process of opening up the file from disk and compiling it into opcode. So not only does it save on compiling the code it also saves the disk access. If your website’s files are located on a distributed filesystem such as NFS then opcode caching will give you upwards of 100% improvement in performance any day of the week.
Plugin is developed to optimize wordpress deployment on varnish + nginx + php-fpm + php-apc server stack using three type of caches full page cache, db cache and opcode cache. This plugin includes nginx-compatibility, db-cache-reloaded-fix for nginx and database cache. This plguin also support varnish cache management with given default.vcl. We have included sample file for nginx and varnish configurations in utils folder. This plugin will automatically invalidate caches upon certain actions from wordpress admin panel.
Clear PHP opcode caches before WordPress Updates: ease the updating process
A second problem is that WordPress sometimes is not able to install and apply updates. An error message “Could not copy file. index.php” followed up with “Installation failed” is displayed in the Dashboard. Stale opcode cache might be the cause of this, and currently there is a running Trac ticket on the subject: Call opcache_reset() after plug-in, theme or core update.
WordPress Performance: What to Know about Modernizing PHP & Opcode Cache
Scott: Most developers know that programming languages add features and fix bugs in new versions. But most languages get faster and improve performance over time as well. PHP 5.2 was released in 2006. In the 9 years between 5.2 and 7.0, PHP has gotten much, much faster. Using an older version (such as 5.2) is like choosing to stick with an original iPhone instead of the latest 6S. Many PHP 7.0 benchmarks have shown up to 2x performance improvements for WordPress sites.
Testing WordPress: the importance of PHP opcode cache
There were some discussions lately at LinkedIn mostly on the topic of choosing a VPS (virtual private server) over a shared hosting provides any benefits. My opinion: a VPS can clearly outnumber a shared host in performance and freedom, but not in pricing. Price can only be matched when the VPS is an unmanaged one, meaning you (or someone you hire) has to take care of all the configurations, the server management, the monitoring - even the operating system install itself.