memcached

When Memcached Slows Your Drupal Site's Performance

For all of the sites we consult on, and manage, we use the excellent memcache module, which replaces the core's database caching. Database caching works for low traffic simple sites, but cannot scale for heavy traffic or complex site.

Recently we were asked to consult on the slow performance of a site with an all authenticated audience. The site is indeed complex, with over 235 enabled modules, 130 enabled rules, and 110 views.

Articles

Installing and Configuring Redis for Drupal 7, and other Memcached Alternatives

For years, we have been using and recommending memcached for Drupal sites as its caching layer, and we wrote several articles on it, for example: configuring Drupal with multiple bins in memcached.

Drupal site excessive memory usage traced to APC and php5-memcached

We were recently troubleshooting a client site running Drupal 7.x, and main complaint was high memory usage on all the site's pages.

We were able to diagnose and solve two main causes that range from the common to unusual.

This is a Drupal 7 Commerce site with 173 modules, and 3 themes enabled. Apache Solr is used for search, and there is custom code to talk over the network to a non-Drupal backend server.

The site runs on a Debian Squeeze Xen VPS.

For most of the site's pages, the client was seeing high memory usage, as follows: