HP StorageWorks 8000 NAS User Manual

Page 228

226 Glossary

networking. The data transfer rate is one gigabit per second (1 Gbps) or

more.

Group Identification

(GID)

A number in the UNIX environment that identifies a group of individuals or

services to a computer system.

Group quota

Lets you restrict the space usage on the NAS server for groups.

Heartbeat

A periodic signal generated by the server to indicate that it is still running.

High availability

High availability characterizes a system that is designed to avoid the loss of

service by reducing or managing failures and minimizing downtime. High

availability implies a service level in which both planned and unplanned

downtime does not exceed a small stated value.

Host Bus Adapter

(HBA)

An HBA is an I/O adapter that sits between the host computer's bus and the

Fibre Channel loop and manages the transfer of information between the two

channels. In order to minimize the impact on host processor performance, the

host bus adapter performs many low-level interface functions automatically or

with minimal processor involvement.

Hot swapping

A feature that allows equipment to be connected to an active device, such as

a computer, while the device is powered on.

Hub

A fibre channel device that connects nodes into a logical loop by using a

physical star topology. Hubs will automatically recognize an active node and

insert the node into the loop. A node that fails or is powered off is

automatically removed from the loop.

IP address

A unique 32-bit value that identifies network hosts using TCP/IP. An IP

address, or block of addresses, is assigned upon application to organizations

responsible for that function. No two network hosts can be assigned the same

IP address. Each address consists of a network number, optional subnetwork

number and host number, written as four numbers separated by periods.

Each number can be 0 to 255.