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Glossary–3
Hitachi Unified Storage VM Product Overview Guide
L
LDEV
logical device
license key
A specific set of characters that unlocks an application and allows it to 
be used. 
logical device (LDEV)
An individual logical data volume (on multiple drives in a RAID 
configuration) in the storage system. An LDEV may or may not contain 
any data and may or may not be defined to any hosts. Each LDEV has a 
unique identifier or “address” within the storage system composed of the 
logical disk controller (LDKC) number, control unit (CU) number, and 
LDEV number. The LDEV IDs within a storage system do not change. An 
LDEV formatted for use by open-system hosts is called a logical unit 
(LU).
logical volume
See volume.
LUN
logical unit number. Sometimes used in place of LU, logical unit.
LUSE
LUN Size Expansion
M
mirror
In Universal Replicator, each pair relationship in and between journal 
groups is called a “mirror”. Each pair is assigned a mirror ID when it is 
created. The mirror ID identifies individual pair relationships between 
journal groups.
modify mode
The mode of operation of Storage Navigator that allows changes to the 
storage system configuration. See also view mode.
P
pair
Two logical volumes in a replication relationship in which one volume 
contains original data to be copied and the other volume contains the