Support has refered me to KB 3011577, which i have read, and has suggested to create a new LUN... NDMP copy the data from the old LUN to the new LUN, and attached to the new LUN -destroy the old LUN. I figure this would be the recommendation...
Completely random thought - I wonder if the LUN move functionality would achieve the same resullt? Probably something to test in a different environment... I imagine not since it uses mirroring instead of an NDMP copy.
"SnapDrive for Windows automatically stops Space Reclaimer in several instances.
During any LUN management operation on a LUN running Space Reclaimer, including LUN disconnect and LUN delete operations
During any Snapshot copy management operation except Snapshot copy rename and delete
On all LUNs of the same storage system volume during Snapshot copy creation
If the SnapDrive service is stopped
During LUN restore operations for any volume mount points directly or indirectly mounted (cascading) from the disk being restored
During Windows host cluster failoverIf a host cluster failover operation occurs on a Windows Server 2003 MSCS or Windows Server 2008 failover cluster while Space Reclaimer is running on a shared LUN, space reclamation will stop running on that LUN.
During any MPIO path management operations, including adding or removing an initiator or active path selection"