Volume—Name of the logical drive for which statistical information is gathered.
Free Space (MB)—Unallocated space on the disk drive in megabytes. One megabyte equals 1,048,576 bytes.
Free Space %—Ratio of the free space available on the logical disk unit to the total usable space provided by the selected logical disk drive.
Queue Length—Average number of both read and write requests that were queued for the selected disk during the sample interval.
Disk Busy Time % (Thresholds Supported)—Percentage of elapsed time that the selected disk drive is servicing read or write requests.