Settings

OPcache is an opcode cache for PHP. It is bundled with PHP 5.5.0 and later. The following settings work really well with Drupal. For Ubunti 14.04 , these following file can be modified to incorporate the changes /etc/php5/apache2/php.ini
Configuration: opcache.enable=1
opcache.memory_consumption=256
opcache.max_accelerated_files=4000
opcache.revalidate_freq=60
opcache.fast_shutdown=1

Disqus is a networked community platform used by hundreds of thousands of sites all over the web. With Disqus, your website gains a feature-rich comment system complete with social network integration, advanced administration and moderation options, and other extensive community functions. Configuring Disqus for Drupal is pretty straightforward. Install the disqus module, enable viewing Disqus comments permissions for anonymous users.

During testing phase of the system, there are WSOD for whom no logs are available. Devel is one option, but for knowing just what might be the reason, the following changes in the settings.php file will reveal any error that occured. <?php error_reporting(E_ALL); ini_set('display_errors', TRUE); ini_set('display_startup_errors', TRUE); ?>