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Debugging a WordPress Network

Debugging a WordPress Network

If you have reached this page, chances are you have received an error in your WordPress network. This failure occurs when WordPress cannot find one or more of the global tables for the network in the database.

On some shared webhosts, the host has disabled the functionality from running. It is always best to check with your webhost before creating a network to make sure your webhost account fulfills the technical requirements.

If You just installed your network

Check your wp-config.php file for :

  • correct database details
  • SUBDOMAIN_INSTALL constant
  • MULTISITE constant
  • $base variable
  • table prefix
  • You should not have anything after
/* That's all, stop editing! Happy blogging. */

/** Absolute path to the WordPress directory. */
if ( !defined('ABSPATH') )
	define('ABSPATH', dirname(__FILE__) . '/');

/** Sets up WordPress vars and included files. */
require_once(ABSPATH . 'wp-settings.php');
Move any code that is after
require_once(ABSPATH . 'wp-settings.php');
to above the stop editing line.


Mod_rewrite not working

Main site works but 404 errors show up when trying to access added child subdomain sites. Ubuntu 10.04 LAMP apache2 install needs these steps:

  sudo a2enmod rewrite
  sudo nano /etc/apache2/sites-avail/default

and change in two places the 'AllowOveride None' to 'AllowOveride all'

  /etc/init.d/apache2 restart

to restart apache2. Note that on more modern versions of Ubuntu the following syntax is preferred (for restarting services such as Apache - also note that in either case you may need to use prepend sudo):

  service apache2 restart

Check the database

Assuming all that is correct, check the database itself and see if all the extra network tables were created. The tables are:

  • wp_blogs
  • wp_blog_versions
  • wp_registration_log
  • wp_signups
  • wp_site
  • wp_sitemeta

If new site creation suddenly stopped working

Please check your database as above. Double-check that the location of the databse server hasn't changed, or is so, that you've updated your wp-config.php file.

Other lesser-known issues

Check that the database user has ALL permissions on the database.

Also, on very few upgrades from WordPressMU to 3.0 and up, a small number of users experienced a problem with creating new sites and receiving errors. This turned out to be a database collation issue.

Check that the .htaccess instructions are not throwing up errors in the Apache logs.

Like this one:

Options FollowSymLinks or SymLinksIfOwnerMatch is off which implies that RewriteRule directive is forbidden:

This will result in a Network install appearing to fail and may show WP errors like

One or more database tables are unavailable. The database may need to be repaired.

Related Articles

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