When creating many cinder volumes simultaneously on XtremeIO backend, several volumes fail to create

Issue

• Attempt to create several, at least 7, volumes simultaneously on the XtremeIO backend.
• Observe an approximately 50% failure rate
• Errors seen in volume.log:

2015-11-23 14:33:36.919 31262 WARNING cinder.volume.drivers.emc.xtremio [req-<uuid> - - -] object 285 of type lun-maps not found
2015-11-23 14:33:36.923 31262 ERROR cinder.volume.driver [req-<uuid> - - -] Unable to terminate volume connection: Resource could not be found.
2015-11-23 14:33:36.924 31262 ERROR cinder.volume.flows.manager.create_volume [req-<uuid> - - -] Failed to copy image <image_uuid> to volume: <volume_uuid>
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume Traceback (most recent call last):
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume   File "/usr/lib/python2.7/site-packages/cinder/volume/flows/manager/create_volume.py", line 501, in _copy_image_to_volume
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume     copy_image_to_volume(context, volume_ref, image_service, image_id)
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume   File "/usr/lib/python2.7/site-packages/osprofiler/profiler.py", line 105, in wrapper
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume     return f(*args, **kwargs)
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume   File "/usr/lib/python2.7/site-packages/cinder/volume/driver.py", line 568, in copy_image_to_volume
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume     self._detach_volume(context, attach_info, volume, properties)
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume   File "/usr/lib/python2.7/site-packages/cinder/volume/driver.py", line 360, in _detach_volume
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume     raise exception.VolumeBackendAPIException(data=err_msg)
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume VolumeBackendAPIException: Bad or unexpected response from the storage volume backend API: Unable to terminate volume connection: Resource could not be found.
2015-11-23 14:33:36.924 31262 TRACE cinder.volume.flows.manager.create_volume