Your customer has tried to delete a volume using HPE OneView interface, but the operation...

The operation to delete a volume using HPE OneView fails because the volume is presented to a server. HPE OneView prevents deletion of volumes that are actively assigned to servers to avoid disrupting operations and data loss. Before deleting the volume, you must unassign it from any server profiles or disconnect it from the servers.

Option A (Correct): Volumes in use cannot be deleted until they are detached.

Option B: There is no "permanent" flag that prevents deletion.

Option C: Having snapshots may prevent deletion on some storage systems, but HPE OneView primarily blocks deletion based on active assignments.

Option D: A rebuilding volume might have restrictions, but the primary reason in this context is active presentation to a server.