A disk array is a disk storage system which contains multiple disk drives. It is differentiated from a disk enclosure, in that an array has cache memory and advanced functionality, like RAID and virtualization.
Components of a typical disk array include:
- Disk array controllers
- Cache in form of both volatile random-access memory and non-volatile flash memory.
- Disk enclosures for both magnetic rotational hard disk drives and electronic solid-state drives.
- Power supplies
Typically a disk array provides increased availability, resiliency and maintainability by using additional, redundant components (controllers, power supplies, fans, etc.), often up to the point when all single points of failure (SPOFs) are eliminated from the design. Additionally those components are often hot-swappable.
Typically, disk arrays are divided into categories:
- Network attached storage (NAS) arrays
- storage area network (SAN) arrays:
- Modular SAN arrays
- Monolithic SAN arrays
- Utility Storage Arrays
- Storage virtualization
Primary vendors of storage systems include EMC Corporation, Hitachi Data Systems, NetApp, IBM, Hewlett-Packard, Oracle Corporation, Dell, Infortrend, Coraid, Inc., Panasas and other companies which often act as OEMs for the above vendors and do not themselves market the storage components they manufacture.
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