Please find the query to pull report from VMAN for datastore space usage with LUN details.
Generally I did not find the parameter LUN name while creating the web-based report. So i pulled it using SQL query.
SELECT [dbo].[VIM_DataStores].Name AS DataStore, [dbo].[VIM_Luns].Name AS LUN, [dbo].[VIM_DataStores].Capacity, [dbo].[VIM_DataStores].FreeSpace, [dbo].[VIM_DataStores].ProvisionedSpace, [dbo].[VIM_DataStores].SpaceUsage
FROM [dbo].[VIM_DataStores]
INNER JOIN [dbo].[VIM_Luns] ON [dbo].[VIM_DataStores].DataStoreID=[dbo].[VIM_Luns].DataStoreID;
Hope i have helped a bit 
This document was generated from the following discussion: Report: Datastores storage report with LUN in place only using VMAN module