Script to check Disk IO

select db_name(database_id) as DatabaseName, file_id,io_stall_read_ms,num_of_reads
,cast(io_stall_read_ms/(1.0+num_of_reads) as numeric(10,1)) as 'avg_read_stall_ms'
,io_stall_write_ms,num_of_writes,cast(io_stall_write_ms/(1.0+num_of_writes) as numeric(10,1)) as 'avg_write_stall_ms',
io_stall_read_ms + io_stall_write_ms as io_stalls,num_of_reads + num_of_writes as total_io,cast((io_stall_read_ms+io_stall_write_ms)/(1.0+num_of_reads + num_of_writes) as numeric(10,1)) as 'avg_io_stall_ms'
from sys.dm_io_virtual_file_stats(null,null)
order by [DatabaseName] desc

Find SQL Server Database file I/O waits

SELECT  DB_NAME(database_id) AS [Database Name] , 

        file_id AS [File ID], 

        io_stall_read_ms AS [Total Read Waits (ms)], 

        num_of_reads AS [Number of Reads], 

        CAST(io_stall_read_ms / ( 1.0 + num_of_reads ) AS NUMERIC(10, 1)) 

            AS [Average Read Wait (ms)] , 

        io_stall_write_ms AS [Total Write Waits (ms)], 

        num_of_writes AS [Number of Writes], 

        CAST(io_stall_write_ms / ( 1.0 + num_of_writes ) AS NUMERIC(10, 1)) 

            AS [Average Write Wait (ms)] , 

        io_stall_read_ms + io_stall_write_ms AS [Total I/O Waits (ms)] , 

        num_of_reads + num_of_writes AS [Number of I/O Operations] , 

        CAST(( io_stall_read_ms + io_stall_write_ms ) / ( 1.0 + num_of_reads 

                                                          + num_of_writes) 

           AS NUMERIC(10,1)) AS [Average I/O Wait (ms)] 

FROM    sys.dm_io_virtual_file_stats(NULL, NULL) 

ORDER BY [Average I/O Wait (ms)] DESC ;