Large Network Problem

If you use the Multisite functionality for more as 10.000 sites inside the network, then will WordPress stop a lot of processes. Also a result for this plugin and it will not list all themes and plugins on the admin pages. But you can change the value for the default. The follow source is a example, copy this in a custom plugin for your network.

add_filter( 'wp_is_large_network', function( $is_large, $type, $count ) {

	if ( ! $is_large )
		return $is_large;

	// $type can be 'sites' or 'users'
	if ( 'sites' !== $type )
		return $is_large;

	// Default is 10000, we add one 0
	return $count > 100000;
}, 10, 3 );

Background: see the issue