A command has been issued to move node data for the specified storage pool but there is already a move node data operation in progress for one or more nodes that have been specifed for that same storage pool.
The server does not process the command.
Check the activity log for a previous MOVE NODEDATA command to determine what processes for moving node data are in progress for the storage pool. Reissue the command for the node(s) and storage pool you desire that are not already in progress, or, reissue the command after the move node data process ends.