Glossary 65
Ldev As it relates to MPE/iX, Ldev refers to an MPE logical device
synonymous with an MPE volume member, MPE device or LUN
created under the control of MPE/iX's SYSGEN utility program.
LDEV Logical device. An LDEV is created when a RAID group is carved into pieces
according to the selected host emulation mode (that is, OPEN-3, OPEN-8,
OPEN-L). The number of resulting LDEVs depends on the selected
emulation mode. The term LDEV is often used synonymously with the term
volume.
LUN Logical unit number. A LUN results from mapping a SCSI 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. For example, a LUN associated with two OPEN-
3 LDEVs has a size of 4,693 MB.
LUSE A LUN is normally associated with only a single LDEV. The LUSE feature
allows a LUN to be associated with 1 to 36 LDEVs. Essentially, LUSE makes
it possible for applications to access a single large pool of storage. The LUSE
feature is available when the HP StorageWorks LUN Configuration Manager
product is installed.
OFC Open Fibre Control.
OPEN-x A general term describing any one of the supported OPEN emulation
modes (for example, OPEN-L).
OS Operating system.
PA Physical address.
path “Path” and “LUN” are synonymous. Paths are created by associating a port,
a target, and a LUN ID with one or more LDEVs.
port A physical connection that allows data to pass between a host and the disk
array. The number of ports on an XP disk array depends on the number of
supported I/O slots and the number of ports available per I/O adapter. The
XP family of disk arrays supports Fibre Channel (FC) ports as well as other
port types. Ports are named by port group and port letter, such as CL1-A.
CL1 is the group, and A is the port letter.
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