HP StorageWorks XP Remote Web Console Software - Manual (Page 55)

Using Multiple Primary and Secondary Storage Systems
System configuration of up to four primary storage systems and up to four secondary storage
systems is allowed for XP Continuous Access Journal operations. Even when there are multiple
primary and secondary storage systems, XP Continuous Access Journal can copy the data in the
primary storage system to the secondary storage system, while maintaining consistency in data
update sequence. Therefore, even if a failure occurs on a large computer system consisting of more
than one storage system, you can continue your business tasks by using data in secondary storage
systems.
Figure 13 (page 55) illustrates an example of using XP Continuous Access Journal in a system
configuration of two primary storage systems and two secondary storage systems.
Figure 13 Configuration Example of Multiple Storage Systems Combination
In the configuration of multiple storage systems combination, the RAID Manager in the primary
host issues time stamp data at regular intervals. The time stamp data is added to the data that will
be written in the XP Continuous Access Journal primary data volume. The secondary storage system
maintains the data consistency by restoring data in chronological order indicated by the time
stamp. Using the time stamp to match the update points of multiple storage systems, XP Continuous
Access Journal can copy data while maintaining consistency.
Usually you can register only one journal group in the consistency group; however, in the
configuration shown in
Figure 13 (page 55) , you can register multiple journal groups in the
consistency group. The following figures show examples where you can register multiple journal
groups:
Using Multiple Primary and Secondary Storage Systems 55