Storage requirements¶

When planning storage for your OpenStack environment, understand the difference between the two types of storage that OpenStack uses: persistent and ephemeral.

The nova-compute service manages ephemeral storage that is used as temporary storage for the operating system of virtual machine instances. When you delete an instance, nova-compute deletes the ephemeral storage as well. If you do not select any additional storage options, the virtual machine volumes will be stored on the local disks of the compute nodes, in the virtual storage partition. However, if you enable Ceph RBD back end for ephemeral volumes, nova-compute stores virtual machine volumes in Ceph.

Persistent storage is the storage that exists outside an instance, in contrast to ephemeral storage.

Fuel deploys storage for the following types of persistent data:

• Glance, for image data, which can use either Swift or Ceph RBD as a storage back end.
• Cinder, for block data, which can use either LVM or Ceph RBD as a storage back end.
• Ceph RadosGW, for object storage, with Ceph RBD as storage back end.