Hitachi Copy-on Write SnapShot, User Manual

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Glossary–11
Hitachi Simple Modular Storage Copy-on-Write SnapShot User’s Guide
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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
R
RAID
Redundant Array of Independent Disks, a disk array in which part of the
physical storage capacity is used to store redundant information about
user data stored on the remainder of the storage capacity. The
redundant information enables regeneration of user data in the event
that one of the array's member disks or the access path to it fails.
Recovery Point Objective (RPO)
After a recovery operation, the RPO is the maximum desired time
period, prior to a disaster, in which changes to data may be lost. This
measure determines up to what point in time data should be recovered.
Data changes preceding the disaster are preserved by recovery.
Recovery Time Objective (RTO)
The maximum desired time period allowed to bring one or more
applications, and associated data back to a correct operational state. It
defines the time frame within which specific business operations or data
must be restored to avoid any business disruption.
remote or target site
Maintains mirrored data from the primary site.
remote path
A route connecting identical ports on the local storage system and the
remote storage system. Two remote paths must be set up for each
storage system (one path for each of the two controllers built in the
storage system).
remote volume stem
In TrueCopy operations, the remote volume (R-VOL) is a volume
located in a different subsystem from the primary host subsystem.
resynchronization
Refers to the data copy operations performed between two volumes in
a pair to bring the volumes back into synchronization. The volumes in a
pair are synchronized when the data on the primary and secondary
volumes is identical.
RPO
See Recovery Point Objective.
RTO
See Recovery Time Objective.