Near-line storage is used by corporations, including
data warehouses, as an inexpensive, scalable
way to store large volumes of data. Near-line storage devices include
DAT and DLT tapes (sequential
access), optical storage such as CD-ROM,
DVD and Blu-ray,
Magneto-Optical which utilize
magnetic heads with an optical reader, and standard also slower P-ATA and
SATA hard disk drives. Retrieval of data is slower
than SCSI hard disk which is usually connected directly
to servers or in a SAN environment. Near-Line implies that whatever media the
information is stored on, it can be accessed via a tape library or some other
method electronically as opposed to off-line which signified some human
intervention is required, such as retrieving and mounting a tape, etc. Near-line
can be slower, but the type of data (historical archives,
backup data, video, etc.,) dictates that the information will not require
instant access and high throughput that SAN and
SCSI can provide and is less expensive per
byte.
