The sites run as a chroot at the PHP level, therefore in most cases you cannot symlink. If you are doing this for static assets only, which are served by the web server, then you are able to do a symlink.
The sites run as a chroot at the PHP level, therefore in most cases you cannot symlink. If you are doing this for static assets only, which are served by the web server, then you are able to do a symlink.