Of a network server, the maintenance of an identical copy of its files in (a) another network server, or (b) a redundant drive in the same server chassis. Note: Mirroring can be used as a rudimentary backup system for the original files, but is more often used to spread out the access load for popular sites, e.g., Web sites, by offering users several different locations from which identical files can be accessed. 2. Of a computer, the maintenance of an identical copy of its files in (a) another computer, or (b) another drive in the same computer chassis.