Performance and scalability

This module provides integration between your Drupal site and the Varnish HTTP Accelerator, an advanced and very fast reverse-proxy system. Basically, Varnish handles serving static files and anonymous page-views for your site much faster than Apache.

This module provides admin-socket integration which allows Drupal to dynamically invalidate cache entries, and also lets you query the Varnish admin interface for status, etc.

COMPATIBILITY NOTE: At the moment, using Varnish at all requires Drupal 7, PressFlow, or the application of a patch for compatible http headers.

Helpful information:

• Gregory Chaix's example VCL

This modules provides following functionality:

Quick common operation

- Enabling and disabling modules through autocomplete suggestions
- Quick search for the nodes, users, etc. to make some operations

Quick Drupal operation

- clear the cache and rebuild permissions from one place or do them both at once

Development tweaks

- show or log backtrace on Drupal errors

PHP Settings

- Increasing PHP max_execution_time value
- Increasing PHP memory_limit value
If your maximum execution time or memory limit is too less, you can experience WSOD (White Screen of Death).
Read more:
http://drupal.org/node/207036 (Increase PHP memory limit)
http://drupal.org/node/482956 (Silent WSODs (White Screen of Death) - fixing step by step)
http://drupal.org/requirements

Database tweaks

This sub-module allow you to enable and change following settings in your database configuration on the fly:
- SQL_BIG_SELECTS
- MAX_JOIN_SIZE
- MAX_ALLOWED_PACKET
- WAIT_TIMEOUT
and changing SQL_MODES

Read more about those variables:
http://dev.mysql.com/doc/refman/5.1/en/server-session-variables.html

And SQL Modes:
http://dev.mysql.com/doc/refman/5.1/en/server-sql-mode.html

Note: It will not work on servers, where your account don't have proper privileges!
You can also follow similar topics:
#361967: Increase MAX_JOIN_SIZE and MAX_ALLOWED_PACKET settings in system.install

This module is for experienced users only. It requires manual configuration of settings.php and maybe also the database and the ability to set up and use subdomains

The split site module optimizes a Drupal site that uses a large number of modules (80 or more) by splitting into a number of smaller sites each using a subdomain. Unlike other multi-site options which use different databases or which split the sites into separate tables, this option minimizes the number of tables that are shared so that the site behaves more like one site.

The module achieves uniformity across the subdomains by attempting to recreate selected menu systems that are shared across each subdomain. This module only works on sites which use a conventional Drupal menu.

For a live example go to Gutpedia and click on 'Jobs' in the left hand menu. This site in entirety uses about 115 modules. By splitting out the jobs, this is reduced to 88 for the main site and 38 for the jobs site, with corresponding performance gains.

Yet another caching system for Drupal with support of memcache, APC, database, file, redis, XCache engines.

More information:

18 Aug 2009 New Drupal "cache" module started.

An experimental integration between CouchDB and Drupal.

Note: this module is a proof of concept / experiment. If you want to help either jump in the issue queue or contact me directly.

Provides API to optimize PNG images using OptiPNG.