HP StorageWorks 1000i Virtual Library System User Manual

Page 119

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iSCSI

Pronounced "eye-scuzzy", an acronym for Small Computer System Interface

protocol over IP network instead of a direct SCSI compatible cable which

enables data blocks to be read from or sent at high speed to a storage device

such as a disk or tape drive

LAN

A local area network (LAN) is a group of computers and associated devices that

share a common communications line or wireless link and typically share the

resources of a single processor or server within a small geographic area (for

example, within an office building).

library

A storage device that handles multiple units of media and provides one or more

drives for reading and writing them, such as a physical tape library and virtual

tape library. Software emulation of a physical tape library is called a virtual

tape library. See also virtual tape library.

logical unit num­

ber (LUN)

An address used in the SCSI protocol to access a device within a target. In the

case of the VLS, a LUN is assigned to each virtual library and tape drive.

LUN mapping

A mechanism of changing the LUN assignments for a specific host.

LUN masking

An authorization process that makes a LUN available to some hosts and

unavailable to other hosts.

master server

A computer that provides administration and control for backup and restore

operations for all clients and servers in a master and media server cluster.

mean time until

data loss (MTDL)

The average time until a component failure can be expected to cause data loss.

This includes the consideration that RAID redundancy can protect against data

loss from the failure of a single component.

media access con­

trol (MAC) address

A low-level unique hardware identifier for every Ethernet port in the world that

is physically stored inside a network card or similar network interface. MAC

addresses are assigned by the IEEE.

media server

A computer whose purpose is to move or copy data from one location to

another, such as from network clients to tape cartridges in a library.

MTBF

Mean Time Between Failures. A statistic that predicts how often failures will

occur.

node

In networks, a processing location. A node can be a computer or some other

device, such as a printer. Every node has a unique network address.

oversubscription

A condition that exists when more virtual media storage is configured on a

VLS than there is physical storage available. Because the VLS dynamically

allocates storage space as user data is written, the VLS allows you to allocate

more storage for virtual media than is physically available.

port mapping

A mechanism of assigning a LUN (virtual device), such as a virtual library or

tape drive, to a specific Fibre Channel host port. Port mapping allows you

to load-balance the LUNs among the Fibre Channel host ports to maximize

bandwidth. At this time, you must manually load-balance the virtual tape drives

in a VLS.

power supply

The computer component that supplies power to a computer. Most personal

computers can be plugged into standard electrical outlets. The power supply

then pulls the required amount of electricity and converts the AC current to DC

current. It also regulates the voltage to eliminate spikes and surges common in

most electrical systems.

processor

The part of a computer (a microprocessor chip) that does most of the data

processing; the CPU and the memory form the central part of a computer to

which the peripherals are attached.

HP StorageWorks 1000i Virtual Library System

119

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