https://kb.netapp.com/support/index?page=content&id=2011404
This is a normal status for a LUN when the volume guarantee has been set to 'none'. The mechanism of volume guarantee is such that with guarantee set to 'volume' or 'file', the space for the LUN inside is already allocated at the aggregate level. Running df -A or checking used space for the aggregate in filer view would show this as used.
A LUN inside a volume will normally contain a lot of empty space (unless the host connected to the LUN fills it). If a volume's guarantee is set to 'none', the total size of the LUN and volume is not allocated at the aggregate layer. Only the actual used space in the LUN will show as used at the aggr level.
