Articles

Informative articles on various technologies ...

This section contains informative articles on various technologies we consult on for our clients.

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Optimizing Drupal Views: Query Time and Rendering Time

A recent client performance assessment consulting project showed that on their site, the main page that logged in users would browse is slow. Tuning the server for memory and disk throughput helped somewhat, but did not fully eliminate the issue.

Looking at the page, it was a view, and the total time was around 2.75 seconds.

The main query was not efficient, with lots of left joins, and lots of filtering criteria:

Drupal Performance and Scalability With Excessive I/O Load Or Memory Exhausion

On many occasions, we see web site performance suffereing due to misconfiguration or oversight of system resources. Here is an example where RAM and Disk I/O severely impacted web site performance, and how we fixed them.

A recent project for a client who had bad site performance uncovered issues within the application itself, i.e. how the Drupal site was put together. However, overcoming those issues was not enough to achieve the required scalability with several hundred logged in users on the site at the same time.

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.

Antibot module for Comment Spam, Alternative to Mollom End Of Life

Acquia has announced the end of life for Mollom, the comment spam filtering service.

Mollom was created by Dries Buytaert and Benjamin Schrauwen, and launched to a few beta testers (including myself) in 2007. Mollom was acquired by Acquia in 2012.

How to configure Varnish Cache for Drupal with SSL Termination Using Pound or Nginx

Secure Socket Layer (SSL) is the protocol that allows web sites to serve traffic in HTTPS. This provides end to end encryption between the two end points (the browser and the web server). The benefits of using HTTPS is that traffic between the two end points cannot be deciphered by anyone snooping on the connection. This reduces the odds of exposing sensitive information such as passwords, or getting the web site hacked by malicious parties. Google has also indicated that sites serving content exclusively in HTTPS will get a small bump in Page Rank.

Diagnosing Slow Drupal Operations Using Linux strace

The other day, we were helping a long time client with setting up a new development server configured with Ubuntu Server LTS 16.04, which comes with PHP 7.x. Benchmarks of PHP 7.x show that it is faster than any PHP 5.x version by a measurable margin, hence the client's attempt to move to the newer version of Ubuntu and PHP.

But when we tried benchmarking the new server against the existing server, which has Ubuntu Server LTS 14.04, showed that the new server is extremely slow compared to the existing one.

Slow Queries In Drupal Can Often Be Cured By Indexes

Recently, we were reviewing the performance of a large site that has a significant portion of its traffic from logged in users. The site was suffering from a high load average during peak times.

We enabled slow query logging on the site for a entire week, using the following in my.cnf:

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.

MongoDB as a caching solution for Drupal 7

MongoDB is a NoSQL database that has Drupal integration for various scenarios.

One of these scenarios is using MongoDB as the caching layer for Drupal.

This article describes what is needed to get MongoDB working as a caching layer for your Drupal site. We assume that you have an Ubuntu Server LTS 14.04 or similar Debian derived distro.