How Can I Resize a Cinder Volume?

Cinder volumes are block storage devices that you attach to instances to enable persistent storage. Resizing of Cinder volumes is not supported yet. Until it becomes supported, you can accomplish the same thing with these steps:

Unmount the Cinder volume from inside the instance:

umount /mnt/volume

Detach the Cinder volume:

nova volume-detach <instanceid> <volumeid>

Snapshot the volume.

Deploy a new volume from the snapshot, with the new size.

See OpenStack Storage Concepts for more information about the OpenStack storage concepts.