Rails 3，显示来自RAILS_ROOT上方的本地文件系统的jpg图像

I'm trying to figure out a way to display images from a mounted file system that is not under RAILS_ROOT (in RedHat or Ubuntu environments). I don't want to use a symbolic link because this app is actually deployed through Tomcat, and Tomcat tries to follow the symbolic link and delete all the images in the mount when I shut down Tomcat. Putting the images under public/images is also not an option due to the number and size of these files.I'm trying to figure out a way to display image