Term | Definition |
direct-attached storage (DAS) | Local data storage; storage of data on the computer itself or on an external device directly plugged into it. |
network-attached storage (NAS) | Storage that’s made available over a network, such as on a centrally accessible file server. |
NAS appliance | Short for network-attached storage appliance. A specialized computer built specifically for network file storage and retrieval. |
storage area network (SAN) | A network storage technology that enables users to interact with a large pool of storage (including multiple devices and media) as if it were a single local volume. |
redundant array of inexpensive disks (RAID) | A technology that attempts to improve performance, data safety, or both by combining multiple physical hard disk drives (HDDs) into a single logical volume. |
RAID0 | A type of RAID that improves performance by striping the data. |
striping | Spreading out data to be stored across multiple discs, and writing to all the discs simultaneously, to improve the speed at which data can be written and read. |
RAID1 | A type of RAID that improves data safety by using mirroring. |
mirroring | Writing an identical backup of a drive’s content to another drive simultaneously, so the data will continue to be available if the main disk fails. |
RAID5 | A type of RAID that combines striping (for performance) with distributed parity (for data protection). |
disk array | A group of disks that work together, such as in a RAID system. |
parity bit | An extra bit written to a disk array during each write operation that helps reconstruct the data in the event of the failure of one of the drives in the array. |