How to genuinely speed up vBulletin
 

Edit .htaccess in your forum root

Codify compression of all HTML, PHP, JavaScript, CSS, images, and pretty much everything using deflate (turn gzip off in the vBulletin options):

AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/atom_xml
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/x-httpd-php
AddOutputFilterByType DEFLATE application/x-httpd-fastphp
AddOutputFilterByType DEFLATE application/x-httpd-eruby

Codify a genuine cache of files for your members

<ifModule mod_expires.c>
ExpiresActive On
ExpiresDefault "access plus 1 seconds"
ExpiresByType text/html "access plus 1 seconds"
ExpiresByType image/gif "access plus 259200000 seconds"
ExpiresByType image/jpeg "access plus 259200000 seconds"
ExpiresByType image/png "access plus 259200000 seconds"
ExpiresByType text/css "access plus 60480000 seconds"
ExpiresByType text/javascript "access plus 21600000 seconds"
ExpiresByType application/x-javascript "access plus 21600000 seconds"
</ifModule>
<ifModule mod_headers.c>
<filesMatch "\\.(ico|pdf|flv|jpg|jpeg|png|gif|swf)$">
Header set Cache-Control "max-age=25920000, public"
</filesMatch>
<filesMatch "\\.(css)$">
Header set Cache-Control "max-age=6048000, public"
</filesMatch>
<filesMatch "\\.(js)$">
Header set Cache-Control "max-age=2160000, private"
</filesMatch>
<filesMatch "\\.(xml|txt)$">
Header set Cache-Control "max-age=2160000, public, must-revalidate"
</filesMatch>
<filesMatch "\\.(html|htm|php)$">
Header set Cache-Control "max-age=1, private, must-revalidate"
</filesMatch>
</ifModule>
<ifModule mod_headers.c>
Header unset ETag
</ifModule>
FileETag None
<ifModule mod_headers.c>
Header unset Last-Modified
</ifModule>

• Configure memcached and use it for everything: vBulletin, VBSEO, vBOptimise, and Supercharge vBulletin modifications.
• See this: http://www.howtoforge.com/using-memc...ad-debian-etch

Alter Apache Configuration:

ExpiresActive On
ExpiresByType image/jpeg "access plus 1 hour"
ExpiresByType image/gif "access plus 1 hour"
ExpiresByType image/png "access plus 1 hour"
ExpiresByType application/x-shockwave-flash "access plus 1 hour"
ExpiresByType application/x-javascript "access plus 1 hour"
ExpiresByType text/css "access plus 1 hour"

Optimize MySQL Server to Consume Less Resources (We reduced MySQL usage from 100% to 40-50% on a board with 50K+ users)

It appears that the MyISAM key_cache is being completely utilized. The key_buffer_size is a buffer that stores referenced MyISAM indexes. The more MySQL can operate from within RAM the more efficient it is. Currently the key_buffer_size is set to 64 MB, and there are over 206 MB of MyISAM specific indexes being stored on the server.

Change buffer_size to 256MB in /etc/my.cnf

In /etc/my.cnf
Log slow queries:

log-slow-queries
log-queries-not-using-indexes

If this table exists in your database index this:

create index idx_termval on seoqueries_terms(term_value(50));

This table is being written to constantly and delaying other queries.

Consider using the Sphinx search engine or applying a protocol called Varnish to your server.

These are suggestions from expert system administrators at RackSpace.com. Special thanks to them for turning our forum into a workhorse and reducing average pageload from 8 seconds to 1.25.