How to use this script is quite simple:

1 - Download the script, open in your access to a tool instance or Server Microsoft SQL Server;

2 - Preferably use for the first runs a development or test environment;

3 - The logged on user must have View Server State permission so you can get the data returned by sys.dm_io_virtual_file_stats Dynamic Management Function that replaces the old fn_virtualfilestats function;

4 - After running note the values given in column [AVG IT Stall in MS], she represents the parameter which we must examine how possible to handle disk latency related reading activities;

5 - The values presented for this column should be identified according to the table below:

< 1ms: unbelievable;
< 3ms: excellent;
< 5ms: very good;
< 10ms: within the expected;
< 20ms: reasonable;
< 50ms: limit;
> 100ms: bad;

> 1 sec: severe disk contention; and

> 15 sec: serious problems with the storage or disk.