The Case for Massive Arrays of Idle Disks ({MAID})
Dennis Colarelli, Dirk C. Grunwald, Michael Neufeld · 2002
The declining costs of commodity disk drives is rapidly changing the economics of deploying large amounts of on-line storage. Conventional mass storage systems typically use high performance RAID clusters as a disk cache, often with a file system interface. The disk cache is backed by tape libraries which serve as the final repository for data. In mass storage systems where performance is an issue tape may serve only as a deep archive for disaster recovery purposes. In this case all data is stored on the disk farm. If a high availability system is required, the data is often duplicated on a separate system, with a fail-over mechanism controlling access.