-- i/o-нагрузка на диски
SELECT SUBSTRING(saf.physical_name, 1, 1)    AS [Диск],
       SUM(vfs.num_of_bytes_read/1048576)    AS [Прочитано (Мб)],
       SUM(vfs.num_of_bytes_written/1048576) AS [Записано (Мб)]
  FROM sys.master_files AS saf
  JOIN sys.dm_io_virtual_file_stats(NULL,NULL) AS vfs ON vfs.database_id = saf.database_id AND
                                                         vfs.file_id = saf.file_id AND
                                                         saf.database_id NOT IN (1,3,4) AND
                                                         saf.type < 2
  GROUP BY SUBSTRING(saf.physical_name, 1, 1)
  ORDER BY [Диск]