Glossary – HP EVA P6000 Storage User Manual
Page 298
Glossary
This glossary defines terms used in this guide or related to this product and is not a
comprehensive glossary of computer terms.
Symbols and numbers
3U
A unit of measurement representing three “U” spaces. “U” spacing is used to designate panel or
enclosure heights. Three “U” spaces is equivalent to 5.25 inches (133 mm).
See also
µm
A symbol for micrometer; one millionth of a meter. For example, 50 µm is equivalent to
0.000050 m.
A
active member of
a virtual disk
family
A simulated disk drive created by the controllers as storage for one or more hosts. An active
member of a virtual disk family is accessible by one or more hosts for normal storage. An active
virtual disk member and its snapshot, if one exists, constitute a virtual disk family. An active
member of a virtual disk family is the only necessary member of a virtual disk family.
See also
adapter
See
.
AL_PA
Arbitrated loop physical address. A 1-byte value the arbitrated loop topology uses to identify the
loop ports. This value becomes the last byte of the address identifier for each public port on the
loop.
allocation policy
Storage system rules that govern how virtual disks are created. Allocate Completely and Allocate
on Demand are the two rules used in creating virtual disks.
•
Allocate Completely—The space a virtual disk requires on the physical disks is reserved,
even if the virtual disk is not currently using the space.
•
Allocate on Demand—The space a virtual disk requires on the physical disks is not reserved
until needed.
ALUA
Asymmetric logical unit access. Operating systems that support asymmetric logical unit access
work with the EVA’s active/active functionality to enable any virtual disk to be accessed through
either of the array’s two controllers.
ambient
temperature
The air temperature in the area where a system is installed. Also called intake temperature or
room temperature.
ANSI
American National Standards Institute. A non-governmental organization that develops standards
(such as SCSI I/O interface standards and Fibre Channel interface standards) used voluntarily
by many manufacturers within the United States.
arbitrated loop
A Fibre Channel topology that links multiple ports (up to 126) together on a single shared simplex
media. Transmissions can only occur between a single pair of nodes at any given time. Arbitration
is the scheme that determines which node has control of the loop at any given moment.
arbitrated loop
physical address
See
arbitrated loop
topology
See
.
array
A synonym of storage array, storage system, and virtual array. A group of disks in one or more
disk enclosures combined with controller software that presents disk storage capacity as one or
more virtual disks.
array controller
See
.
array controller
failover
The process that takes place when one controller assumes the workload of a failed companion
controller.
array-based
management
A management structure in which HP P6000 Command View is installed on the management
module within the EVA controller enclosure.
298 Glossary