HP StorageWorks XP Remote Web Console Software User Manual
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Figure 15 Using More Than One Primary and Secondary Subsystem for Remote Copy
When primary hosts write data to primary data volumes, the hosts add time stamp to the data.
Secondary subsystems check time stamps and then restore data to data volumes in chronological
order (older data are restored earlier), so that data update sequence is maintained.
This manual uses the term "arbitration processing", which refers to execution of the journal restore
function based on time stamps in an attempt to maintain data update sequence. When there is
more than one secondary subsystem, one of the secondary subsystems controls the other secondary
subsystems, compares time stamps of data received by all the secondary subsystems (including
the local subsystem), and then performs arbitration processing. In this manual, the term "supervisor
DKC" is used to see the subsystem that performs arbitration processing. Also, the term "subordinate
DKCs" is used to see the subsystems that are controlled by the supervisor DKC and are targets of
arbitration processing. In the example in Figure 3.8, the secondary subsystem 1 is the supervisor
DKC, and the secondary subsystems 2 and 3 are subordinate DKCs.
To perform arbitration processing, the supervisor DKC must be connected with the subordinate
DKCs. For details on connections between secondary subsystems,
The following sections explain more detail about primary and secondary storage systems.
•
•
“Hardware Configuration (When More Than One Primary and Secondary Storage System
are Used)” (page 57)
•
“Setup Procedure (When More Than One Primary and Secondary Subsystem are Used)” (page
57)
•
“Extended Consistency Groups” (page 57)
•
“Connections Among Secondary Storage Systems” (page 61)
•
“Disaster Recovery for Multiple Primary and Secondary Storage Systems” (page 62)
Using More Than One Primary and Secondary Storage System for Remote Console
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