[Cinder][driver][ScaleIO]

Hello,

We are using EMC ScaleIO as our backend to cinder. When we delete VMs that have attached volumes and then try deleting said volumes, the volumes will sometimes end in state error_deleting. The state is reached because for some reason the volumes are still mapped (in the ScaleIO sense of the word) to the hypervisor despite the VM being deleted. We fixed the issue by setting the following option to True in cinder.conf:

# Unmap volume before deletion. (boolean value) sio_unmap_volume_before_deletion=False

What is the reasoning behind this option? Why would we ever set this to False and why is it False by default? It seems you would always want to unmap the volume from the hypervisor before deleting it.

Thank you,

Martin