HP StorageWorks P9000 User Manual page 108

Glossary
array group A group of four or eight physical hard disk drives (HDDs) installed in a P9000 or XP disk array
and assigned a common RAID level. RAID1 array groups consist of four (2D+2D) or eight HDDs
(4D+4D). RAID5 array groups include a parity disk, but also consist of four (3D+1P) or eight
HDDs (7D+1P). All RAID6 array groups are made up of eight HDDs (6D+2P). This is also known
as a parity group or a RAID group.
BC P9000 or XP Business Copy. An HP application that provides volume-level, point-in-time copies
in the disk array.
bit The basic unit of data in a binary numbering system (binary digit), represented by a 0 or a 1.
Eight bits equals one byte.
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-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.
CT group Consistency group.
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.
failover The process that occurs when one device assumes the workload of a failed companion device.
Failovers can be planned or unplanned.
FBA Fixed-block architecture.
FC-AL Fibre Channel arbitrated loop.
fence level A method of setting rejection of P9000 or XP Continuous Access write I/O requests from the host
according to the condition of mirroring consistency.
Fibre Channel A data transfer architecture designed for mass storage devices and other peripheral devices that
require high bandwidth.
GUID Globally unique identifier.
HDD Hard disk drive.
instance A running copy of RAID Manager. Instances can be local or remote. Multiple instances can run
on the same host.
LDKC Logical disk controller.
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.
P-VOL Primary volume.
108 Glossary