Features Of Paired Volumes; Figure 2.1 Concept Of Paired Volumes - Hitachi TAGMASTORE MK-90RD011-25 User Manual

2.2

Features of Paired Volumes

The logical volumes, which have been handled independently by server machines, can be
combined or separated in a pair being handled uniformly by the Hitachi TrueCopy and/or
ShadowImage pairing function. Hitachi TrueCopy and ShadowImage regard those two
volumes to be combined or separated as unique paired logical volume used by the servers. It
is possible to handle paired volumes as groups by grouping them in units of server software
or in units of database and its attribute.
Server A Server B
Special files
Special files
Oradb
Oradb
A and B
C and D
Group name: oradb
Volume A Volume C
Oradb1
Paired logical volume
Volume B Volume D
Oradb2
Paired logical volume
Local volume space of server A
Server C
Special files
Oradb
C and D
Figure 2.1 Concept of Paired Volumes
Addressing paired logical volumes: The correspondences between the paired logical
volumes and physical volumes are defined by users by describing any intended paired logical
volume names and group names in the configuration definition file of each server. It is
possible to define a server for the paired logical volumes in units of group name. Each paired
logical volume must belong to a group in order to determine the corresponding server.
Specification of volumes by commands: Volume names to be specified by the TrueCopy
commands must be given using the paired logical volume names or the group names.
Hitachi Command Control Interface (CCI) User and Reference Guide 9