massive array of idle disks
In storage terminology a massive array of idle disks, or MAID as it is abbreviated, is a technology that uses a large group of hard disk drives, hundreds or even thousands, with only those drives that are needed actively spinning at any given time. MAID is a storage system solution that reduces both wear on the drives and also reduces power consumption. Because only specific disks spin at a given time, what is not in use is literally a massive array of idle disks, which also means the system produces less heat than other large storage systems.
One type of MAID is called the Copan array (Copan Systems Inc.). The Copan array treats drives in the array similar to a tape library (VTL) where only what is needed is actually powered. A Copan array can contain hundreds of terabytes of disks which share supply, controller, and cabinet.
See also disk array.