#sys.dm_io_virtual_file_stats

Query SQL Server Database File I/O Statistics

A SQL Server instance with one database (or hundreds) often has its database files spread across multiple physical drives to help with the read/write performance. However, as more and more databases are added to the server, the read/write activity among the drives can become unbalanced and slower than acceptable. One drive could be taking a heavier workload than others and become the performance…