What is the actual impact of file fragmentation upon I/O performance?
The “Physical Device Extended Metrics” provided by hIOmon include several metrics related to physical device “split I/O” operations (which can occur, for example, when the data requested by a file I/O operation resides upon noncontiguous areas of the physical device so that multiple physical device I/O operations must be performed to satisfy the file I/O operation). These new metrics can help provide, for instance, empirical data (moreover based upon actual file I/O operations) regarding the issue of file fragmentation by helping to show the actual performance impact of accessing fragmented files and of file fragmentation overall.
