We tend to think of Linux as a general-purpose operating system, but it also makes a great foundation for special-purpose software appliances.
One of the more interesting releases, in this regard, is the storage management operating system, Openfiler.
Xinit Systems Openfiler is designed from the bottom up as both a file-based NAS (network-attached storage) and block-based SAN (storage area network) system manager.
To connect these together, Openfiler is designed for use with iSCSI (Internet SCSI) devices.
Basically, iSCSI involves the use of standard SCSI drive commands over a TCP/IP connection.
Typically, this means that the SCSI initiator (typically, a server) accesses remote drives as block devices over Gigabit or 10 Gigabit Ethernet.
From a users viewpoint, it appears that these remote drives are co-located with the server.
This, in turn, gives businesses relatively inexpensive access to terabytes of storage without the expense of Fibre Channel SANs.