This article is from the storage FAQ part1, by Rodney D. Van Meter with numerous contributions by others.
Originally developed at our institute for use in radio astronomy, the DataVast is now being built and marketed by DataVation. DataVast is an SVHS tape array with up to 30 tape transports and a capacity of 50 GBytes uncompressed per tape (1.5 TB total with 30 transports). DataVast is best suited for near-line networked applications. It sits on an Ethernet network and acts as an NFS file server. An internal 4 GB disk serves as a cache for recently accessed files. Except for the fact that files often take longer to access, the system appears exactly like an extremely large disk. File "seek" times depend on user access patterns and file sizes, but most users can expect average access times under 1 minute and worst-case access times under 3 minutes. Data transfer rates are comparable with typical Ethernet NFS servers. DataVast is not redundant in the sense of a RAID -- the array architecture is used to increase capacity and reduce cost (the main electronics is replicated only once for up to 30 tape transports, unlike SCSI RAIT systems where each tape drive duplicates all electronics). There is no robotics. See http://www.datavation.com. VastNSS is Vast Network Storage Server. This was known as VastNSS, owned by Legacy, but some of the guys split and bought the technology and founded Datavation, and renamed the product DataVast. (rdv, 97/3/18) (info updated courtesy of Michael Mansell, email@example.com, 97/3/18)