OpenStack requires block and object storage. You must provision both of these types. 
The following services provide storage for OpenStack:

* Cinder 
  Cinder provides persistent block storage that is virtual machine volumes

* Swift
  Swift delivers object storage that communicates with the OpenStac `glance` service which provides access to 
  virtual machine images and snapshots.

* Ceph
  The Ceph project combines block and object storage. Ceph creates multiple copies of data, which provides redundancy 
  and eliminates the single point of failure.