HP StorageWorks XP Remote Web Console Software - Manual (Page 21)

2 Overview of Universal Replicator
Operations
This chapter provides an overview of Universal Replicator operations:
Functionality Overview
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.
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 1 on page 22 shows an overview of UR operations.
Hitachi Universal Replicator for z/OS user guide for XP12000/XP10000 Disk Arrays and SVS 200 21