In the Drupal community, we always recommend using the Drupal API, and best practices for development, management and deployment. This is for many reasons, including modularity, security and maintainability.
But it is also for performance that you need to stick to these guidelines, refined for many years by so many in the community.
Do you have a problem with some Drupal admin pages with a large number of input fields not saving? Does the page just returns back with no message confirming that changes have been saved?
Well, this happened recently on a site that we were troubleshooting for a client.
The symptoms were: trying to save has lots of input fields, a) comes back with no message about saving changes, and b) the values changed were not saved.
The site had 210 enabled modules, 14 user roles defined, and 84 content types, with 76 content fields!
We recently wrote on a botnet attack hammering web site causing outages.
In the past few days, we have seen another Denial of Service attack on a client's site.
The symptoms were a complete outage of the server, with very high CPU usage, and high load average (over 900 in some cases!).
Upon investigating, we found that this is caused by the following hits:
22.214.171.124 - - [22/Jul/2012:19:55:07 -0400] "POST / HTTP/1.1" 500 539 "-" "-"
Recently a client complained that their site has been suffering from slow downs that were not there before.
Upon investigating the history of resource utilization, we found that memory usage has increased, and at the same time, the load average has increased as well.
To cut a long story short, we found out that initially, the site had neither dblog nor syslog modules were enabled, and they were enabled before the issues started. They started when syslog was enabled.
One of the things that a default Drupal installation does is that it handles 404s for static files within Drupal itself. In other words, a 404 for a .css or .jpg file causes a full Drupal bootstrap. This is not necessary, and wastes resources on a site that gets lots of 404s: lots of code is executed, many database queries are performed, only to return a 404 for a static file.
Is your Drupal site slow?