HP StorageWorks XP Remote Web Console Software - Manual (Page 24)

2-2 Chapter 3 Preparing for Universal Replicator z/OS Operations
Hitachi Universal Replicator for IBM /OS User’s Guide
Functionality Overview
Hitachi Universal Replicator represents a unique and outstanding disaster
recovery solution for large amounts of data that span multiple volumes. The
UR group-based update sequence consistency solution enables fast and
accurate database recovery, even after a “rolling” disaster, without the need
for time-consuming data recovery procedures. The user-defined UR journal
groups (volume groups) at the secondary site can be recovered with full
update sequence consistency but behind the primary site due to asynchronous
copy operations. This functionality also provides protection for write-
dependent applications in the event of a disaster.
UR enables you to create duplicate volumes by copying data from the primary
data volumes in the primary storage system to the secondary data volumes in
the secondary storage system at the remote location. To perform this function,
the journal obtain function at the primary site, the journal copy function
between the primary and secondary sites, and the journal restore function at
the secondary site are performed sequentially with the primary and secondary
data volumes and the journal volumes. Write sequence consistency for the
primary data volume at the primary site is also maintained for the secondary
data volume at the secondary site by the write sequence number to be
assigned for the journal data with the journal obtaining function, enabling you
to configure the duplicate system which has data integrity. UR reduces the
occurrence of pair suspensions due to restrictions of data transfer from the
primary site to the secondary site by storing the write data from the host in
the master and restore journal volumes, providing a high-reliability duplication
system.
Figure 2-1 UR Components for Fibre-Channel Connection shows an overview of
UR operations.