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Directories and Storage Services Glossary

A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S T
U
V
W
X
Y
Z

A

Active Accounts

Live accounts which staff and students use to authenticate with the Novell eDirectory.  When staff and students leave, accounts are made 'inactive' and are eventually deleted once a holding period has expired.

F

FC disk
Fibre Channel based disks are available in sizes of 146GB and 300GB with rotational speeds of 10,000 and 15,000 rpm.
Full Backup Window
The start and finish time allocated to complete a full weekly backup

H

HBA
Acronym for Host Bus Adapter.  A special kind of network card used to connect a host server to a SAN
Host server
A server attached to the storage network, which can have storage volumes assigned to it

L

LUN
Acronym for Logical Unit Number.  "LUN" refers either to the storage volume itself, or (more strictly correct) a number (1-255) which refers to the connection between the host server's HBA and the storage volume.

N

Network-attached storage (NAS)

As distinct from Storage Area Network (SAN), Network-Attached Storage, or NAS, is a term for a device containing one or more hard disks which is capable of being attached directly to a network.  It provides access to the storage for other servers attached to the same network.  Essentially a NAS device is a small server with limited functionality whose sole job is to make its storage available on the network.  It also often provides a web page on the network for remote configuration of the device and its storage.

P

permissions
Permissions may be assigned at a directory level, to a group of staff accounts, with either Full Control or Read Only rights. Staff can be added or removed from specific groups to change their access for each directory.

S

SATA disk
Serial ATA based disks are available in sizes of 500GB with a rotation speed of 7,200 rpm.
Storage Area Network (SAN)
Acronym for Storage Area Network.  A collection of high capacity, high performance storage units linked together by a fibre optic network.  To get access to the storage, a host server needs to be linked to the SAN using a special network card called an HBA
Storage controller
The "brains" in a storage area network disk system.  This manages the disk allocations and directs all the data between the storage and the host servers.
Storage network
The physical network linking the IT Services SAN storage hardware to departmental host servers
Storage virtualisation

Uses a "smart" software layer between the disk storage and the host server.  This gives many more options to how disk data is presented and how it can be accessed.  "Thin" volume provisioning, volume copies, moving data between different disk types, can all be accomplished without interrupting the host server's connection with its data. 

Storage volume
A single allocation of storage presented to one or more host servers

T

Thin provisioning

A way of presenting storage to a server so that although it looks like a very large volume is available, the system uses just enough disk storage to hold the actual amount of data saved.  See Thin provisioning in the SAN technical detail section.