Nova's ephemeral storage using cinder as backend

Currently we can use local storage or shared fs(like NFS) as the ephemeral storage. For support live migation, in normally we will use shared fs. But maintenance a shared fs is extra cost. That means admin need maintenance different storage system for nova's ephemeral storage, glance and cinder. For some small deployment scene, we can use cinder for nova's ephemeral storage. And glance also support cinder. Then admin just maintenance only one storage system for glance, cinder and nova. So for small deployment scene, admin just need use only one san storage system for openstack deployment.