HP StorageWorks XP Remote Web Console Software - Manual (Page 10)

2 Overview of Universal Replicator for Mainframe
Operations
URz provides a RAID storage-based hardware solution for disaster recovery which enables fast
and accurate system recovery. Once URz operations are established, duplicate copies of data are
automatically maintained for backup and disaster recovery purposes. During normal URz operations,
the primary data volumes remain online to all hosts and continue to process both read and write
I/O operations. In the event of a disaster or system failure, the secondary copy of data can be
rapidly invoked to allow recovery with a very high level of data integrity. URz can also be used
for data duplication and migration tasks.
URz represents a unique and outstanding disaster recovery solution for large amounts of data that
span multiple volumes. The URz 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 URz 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.
URz provides update sequence consistency for user-defined journal groups that contain multiple
data volumes (for example, large databases), as well as protection for write-dependent applications
in the event of a disaster.
When URz is used, data to be copied will be temporarily stored in journal volumes, which are a
type of logical volumes. UR enables you to configure and manage highly reliable data replication
systems, by using journal volumes to reduce chances of suspension of copy operations; copy
operations can be suspended due to restrictions on data transfers from the primary site to the
secondary site.
Overview of URz Functionality
URz 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. URz 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 1 (page 11) shows an overview of UR operations.
10 Overview of Universal Replicator for Mainframe Operations