HP XP P9500 Storage - Manual (Page 154)

Glossary
allocation The ratio of allocated storage capacity versus total capacity as a percentage. Allocated storage
refers to those logical devices (LDEVs) that have paths assigned to them. Allocated storage capacity
is the sum of the storage of these LDEVs. Total capacity is the sum of the capacity of all LDEVs
on the disk array.
CHA Channel adapter. A device that provides the interface between the array and the external host
system. Occasionally, this term is used synonymously with the term channel host interface processor
(CHIP).
CLPR Cache logical partition.
Cnt Ac-J P9000 or XP Continuous Access Journal software.
Cnt Ac-J Z The version of Continuous Access Journal that supports mainframe volumes.
Cnt Ac-S P9000 or XP Continuous Access Synchronous software.
Cnt Ac-S Z The version of Continuous Access Synchronous that supports mainframe volumes.
command device A volume in the disk array that accepts Continuous Access, Business Copy, or P9000 for Business
Continuity Manager control operations, which are then executed by the array.
CU Control Unit. Used to organize the storage space attached to the disk controller ( DKC). You can
group similarly configured logical devices (LDEVs) with unique control unit images (CUs). CUs
are numbered sequentially. The disk array supports a certain number of CUs, depending on the
disk array model. Each CU can manage multiple LDEVs; therefore, both the CU number and the
LDEV number are required to identify an LDEV.
DKA Disk adapter.
DKC Disk controller.
ESW Express switch adapter.
Fibre Channel A data transfer architecture designed for mass storage devices and other peripheral devices that
require high bandwidth.
HBA Host bus adapter.
HDD Hard disk drive.
LUN Logical unit number. A LUN results from mapping a logical unit number, port ID, and LDEV ID to
a RAID group. The size of the LUN is determined by the emulation mode of the LDEV and the
number of LDEVs associated with the LUN.
LUSE Logical Unit Size Expansion. The LUSE feature is available when the HP StorageWorks LUN
Manager product is installed, and allows a LUN, normally associated with only a single LDEV,
to be associated with 1 to 36 LDEVs. Essentially, LUSE makes it possible for applications to access
a single large pool of storage.
MCU Main control unit.
parity group A set of hard disk drives that have the same capacity and that are treated as one group. A parity
group contains both user data and parity information, which enables user data to be accessed
if one or more drives in the group is not available.
path A path is created by associating a port, a target, and a LUN ID with one or more LDEVs. Also
known as a LUN.
PAV Parallel access volume.
port A physical connection that allows data to pass between a host and the disk array. The number
of ports on a disk array depends on the number of supported I/O slots and the number of ports
available per I/O adapter. The P9000 and XP family of disk arrays supports Fibre Channel (FC)
ports and other port types. Ports are named by port group and port letter, such as CL1-A. CL1 is
the group; A is the port letter.
RAID level A configuration of disk drives that uses striping, mirroring, and parity to improve performance
and data availability and reliability.
154 Glossary