Glossary of Storage Terms


  • Direct-attached storage (DAS): As the name implies, storage attached directly to a server.

  • Fibre Channel: The method by which data is transferred between two ports via fiber optic cable. Fibre Channel is designed to support speeds of up to 100 Mbps, though there are proposals for higher-speed standards.

  • Fibre Channel-Over-IP (FCIP): A standard for tunneling Fibre Channel packets over IP networks.

  • Fibre Channel Protocol (FCP): Standard for providing

    a serial SCSI interface to the OS, allowing systems to be addressed as SCSI devices without modifying the OS.

  • Host-bus adapter (HBA): An I/O adapter that provides processing and connects a host's I/O bus between a host and storage.

  • Internet Fibre Channel Protocol (iFCP): A standard for switching Fibre Channel over IP networks by translating packets, rather than encapsulating them.

  • Internet SCSI (iSCSI): A proposed standard from the Internet Engineering Task Force that encapsulates SCSI commands into TCP packets, allowing for the transport

    of I/O block data over IP networks. It is seen as one of the key standards to bridge SCSI and Ethernet with

    SANs, enabling remote mirroring, backup and

    disaster-recovery.

  • Network-attached storage (NAS): Devices that

    connect to a network typically to consolidate file-level

    data running on servers.

  • Small Computer System Interface (SCSI): A group of ANSI standards and proposed specifications that define I/O bus connectivity. SCSI is primarily designed for connecting storage subsystems to hosts through HBAs.

  • Storage-area network (SAN): A network designed to transfer data between hosts and storage elements. The first SANs were deployed in 1998 and, until recently, have been used in large data centers for block-level or

    database-oriented data.

  • TCP offload engine (TOE): A new class of devices that performs the function of an HBA for iSCSI connectivity.

  • Virtualization: An emerging form of managing multiple SANs and storage arrays through management software, intended to ease administration, hide complexity and

    add security.