Good question. It is possible to run drupal multisites as a subdirectory even if your Drupal installation is in a subdirectory itself.
Side note: the /sites/ directory in your examples is not necessary.
Given that your main Drupal install is accesible at
domain.com/drupal the solution is to use symlinks to tell your webserver that the document root for
domain.com/drupal/multisite is the same as your main drupal install (
The first step is to create a directory for the multisite. The syntax is a little different for subdirectory multisites:
domain.com.multisite. So, inside your
/sites directory, you will have something like this:
Place a copy of
domains.com.multisite and rename it to
Then create the symlink described above by running the following command from your main website's docroot (not Drupal's docroot, the main website's docroot - usually
public_html or something similar):
ln -s [drupal-directory-name] [multisite-directory-name]
Or, using the names in our example above:
ln -s drupal multisite
See Drupal's multisite documentation for more information.