Glossary

client

A computer that shares files on a storage system. See also host.

HBA

Host bus adapter. An I/O adapter that connects a host I/O bus to a computer's memory system in SCSI environments. The HBA might be an FCP adapter or an iSCSI adapter.

host

Any computer system that accesses data on a storage system as blocks using the iSCSI protocol, or is used to administer a storage system.

igroup

Initiator group. A collection of unique iSCSI node names of initiators (hosts) in an IP network that are given access to LUNs when they are mapped to those LUNs.

initiator

The system component that originates an I/O command over an I/O bus or network; a host that has iSCSI initiator software installed on it, or a host that has a host bus adapter (HBA) installed in it, which is connected to the iSCSI or FCP network with the appropriate license enabled.

initiator group

See igroup.

iSCSI

A licensed service on the storage system that enables you to export LUNs to hosts using the SCSI protocol over TCP/IP.

iSCSI node name

A logical name to identify an iSCSI node, with the format iqn.yyyy-mm.backward_naming_authority:sn.unique_device_name.

yyyy-mm is the month and year in which the naming authority acquired the domain name.

backward_naming_authority is the reverse domain name of the entity responsible for naming this device. An example reverse domain name is com.microsoft.

unique_device_name is a free-format unique name for this device assigned by the naming authority, preceded by sn. Typically, the unique_device_name is a serial number.

LUN

A logical unit of storage.

LUN clone

A complete copy of a LUN, which was initially created to be backed by a LUN or a file in a Snapshot copy. The clone creates a complete copy of the LUN and frees the Snapshot copy, which you can then delete.

LUN ID

The numerical identifier that the storage system exports for a given LUN. The LUN ID is mapped to an igroup to enable host access.

LUN path

The path to a LUN on the storage system. The following example shows a LUN path:

LUN path Mapped to LUN ID --------------------------------------------/vol/vol01/iscsidb.lun igroup_1 6

LUN serial number

The unique serial number for a LUN, as defined by the storage system.

map

To create an association between a LUN and an igroup. A LUN mapped to an igroup is exported to the nodes in the igroup (iqn or eui) when the LUN is online. LUN maps are used to secure access relationships between LUNs and the host.

online

Signifies that a LUN is exported to its mapped igroups. A LUN can be online only if it is enabled for read/write access.

offline

Disables the export of the LUN to its mapped igroups. The LUN is not available to hosts.

qtree

A special subdirectory of the root of a volume that acts as a virtual subvolume with special attributes. You can use qtrees to group LUNs.

SAN

Storage Area Network. A storage network composed of one or more storage systems connected to one or more hosts in either a direct-attached or network-attached configuration using the iSCSI protocol over TCP/IP or the SCSI protocol over FCP.

share

An entity that allows the LUN's data to be accessible through multiple file protocols such as NFS and iSCSI. You can share a LUN for read or write access, or all permissions.

space reservations

An option that determines whether disk space is reserved for a specified LUN or file remains available for writes to any LUNs, files, or Snapshot copies. Required for guaranteed space availability for a given LUN with or without Snapshot copies.

storage system

Hardware and software-based systems that serve and protect data using protocols for both SAN and NAS networks.

target

The system component that receives a SCSI I/O command. A storage system with the iSCSI or FCP license enabled and serving the data requested by the initiator.

volume

A file system. Volume refers to a functional unit of storage on a storage system, based on one or more RAID groups, that is made available to the host. LUNs are stored in volumes.

WWN

World Wide Number. A unique 48- or 64-bit number assigned by a recognized naming authority (often through block assignment to a manufacturer) that identifies a connection for an FCP node to the storage network. A WWN is assigned for the life of a connection (device).

WWNN

Worldwide node name. A unique 64-bit address represented in the following format: nn:nn:nn:nn:nn:nn:nn:nn, where n represents a hexadecimal value. A WWNN is assigned to a storage system based on the serial number of its NVRAM. The WWNN is stored on disk. Data ONTAP refers to this number as a Fibre Channel node name, or simply, a node name.

WWPN

Worldwide port name. A unique 64-bit address represented in the following format: nn:nn:nn:nn:nn:nn:nn:nn, where n represents a hexadecimal value. Each Fibre Channel device has one or more ports that are used to connect to a SCSI network. Each port has a unique WWPN, which Data ONTAP refers to as an FC Portname, or simply, a port name.