HP StorageWorks XP Remote Web Console Software - Manual (Page 86)

3-20 Chapter 3 Preparing for Universal Replicator z/OS Operations
Hitachi Universal Replicator for IBM /OS User’s Guide
5. The secondary storage system 1 (i.e., the supervisor DKC) performs
arbitration processing. In other words, the secondary storage system 1
restores journal data of the secondary storage systems 1 and 2, based on
the time stamps and the sequence numbers added to the journal data, so
that consistency with the primary data volume is maintained.
The flow of the arbitration processing is as follows:
1. From journal data in restore journal groups registered in the extended
consistency group, the supervisor DKC collects time stamps of journal data
have not been restored.
2. The supervisor DKC compares the time stamps, and then selects the oldest
time stamp.
3. The supervisor DKC requests the subordinate DKCs to restore the journal
data that has the selected time stamp.
4. From journal data having the time stamp and earlier time stamps, the
subordinate DKCs restore all journal data that have not been restored, in
the order of the sequence numbers.
Hardware Configuration for Multiple Primary and Secondary
Storage Systems
This section explains hardware configuration when more than one primary and
secondary storage system are used.
It is recommended that Business Continuity Manager is installed on the host in
the primary and secondary sites. Storage Navigator PCs must be installed in
both of these sites. Also, storage system settings must be made so that
Business Continuity Manager can be used. For detailed information about
settings required for using volumes in a remote site, please refer to Business
Continuity Manager User's Guide.
Up to four primary storage systems and up to four secondary storage systems
can be used. For example, you can use four primary storage systems and four
secondary storage systems. Also, you can use two primary storage systems
and one secondary storage system.
The supervisor DKC and subordinate DKCs must be mutually connected in the
secondary site, so that arbitration processing can be performed. Also, remote
command devices must be created in the supervisor DKC. For details on
secondary storage systems connections and remote command devices, see the
next section and the Universal Volume Manager User's Guide.