OpenStack: Does Cinder volume with NFS driver support space reclaimation?
OpenStack Cinder volume driver
No.A Cinder volume corresponds to a file within the NFS share provided by a FlexVol.The space is consumed when you write actual data in the Cinder volume.
ONTAP is not able to read the filesystem within the Cinder volume to tell if a block is in use or not, so removing a file inside the Cinder volume won't free space. Only when you delete the Cinder volume, the corresponding file within the NFS share will be deleted, and the space will be reclaimed.