Comment 0 for bug 1602193

Description

A second ephemeral disk to be considered as an image, then the backing file is not deleted when it is anymore not used.
After some instance create/delete period, the hypervisor local storage capacities are reduced ... and will decrease and decrease.

Actual result on mitaka

- boot an instance with a flavor with an ephemeral disk
- on the hypervisor, two backing files were created in /var/lib/nova/instances/_base. One for the image and an other one for the ephemeral disk
- delete of the previous instance
- if remove_unused_base_images = True, then after a while the backing file for image is deleted (if it's not used by another instance), but not the backing file for ephemeral disk

Excepted result

If it's not used by another instance, the backing file for ephemeral disk must be also deleted.