This module generates a RewriteMap file which can be used to redirect requests for internal URLs to the corresponding alias. This allows the redirect to occur on the Apache level instead of requiring Drupal to bootstrap in order to handle the redirect thus removing significant load from the webserver to handle the redirects.
Usage
Install Drupal with Global Redirect module and this Global Redirect RewriteMap module.
Go to admin/config/system/globalredirect and configure settings for Global Redirect and near the bottom are the options for this Global Redirect RewriteMap module. Use the manual generation button to create an initial RewriteMap file.
The RewriteMap Apache directive cannot be used in the .htaccess context so the the following configurations must be placed in the server or virtual host configuration.
RewriteEngine On
RewriteMap globalredirect txt:path/to/private/files/globalredirect_rewritemap.txt
Configure your .htaccess file to use the RewriteMap defined in step 3. Place these in your .htaccess just before the comment that says "# Pass all requests not referring directly to files in the filesystem..." You will also likely need to set the RewriteBase in your .htaccess. # Global Redirect RewriteMap
RewriteCond ${globalredirect:$1} > "" [NC]