(
Massive
Array of
Idle
Disks) Active archiving that uses disk drives instead of tape. Most of the drives in a MAID array are idle most of the time, but can be revved up and read faster than searching sequentially through magnetic tape. MAID libraries typically do not use RAID technology because each read and write in most RAID configurations uses several drives. The concept behind MAID is to have an enormous amount of data quickly available at the least cost, and spinning disks require power and generate heat, which requires cooling.
Some Active, Some Passive
A MAID system may be built with a small ratio of spinning disks that serve as a cache for the non-spinning, passive disks. If a request is not found in the cache, the appropriate passive disks are powered up. See
active archiving,
WORO and
RAID.