This read-only counter tracks the total number of read operations performed on this disk device since the host last booted. Admins use it alongside diskIONRead to calculate average read size and to monitor read operation rates, useful for spotting a disk suffering from many small, inefficient reads. Dividing diskIONRead by diskIOReads over a polling interval gives the admin the average bytes-per-read for this disk, useful for characterizing its I/O pattern.