Hitachi Universal Replicator for z/OS User Guide: HP XP12000 Disk Array, HP XP10000 Disk Array, HP 200 Storage Virtualization System (T1778-96021, May 2011)

2 and 3 and secondary subsystems 2 and 3. If you restore data volume pairs in journal group
1, the supervisor DKC will execute arbitration processing on journal groups 1 and 3.
NOTE: When you collectively split data volumes pairs in a specific journal group in an
extended consistency group, you cannot use the REVERSE option of the Business Continuity
Manager YKSUSPND command.
• Removing journal groups from extended consistency groups:
You can remove journal groups from an extended consistency group anytime, regardless of
the status of the journal groups. Also, if you delete all data volumes from a journal group in
an extended consistency group, the journal group will automatically be removed from the
extended consistency group.
Removal of journal groups from an extended consistency group does not stop remote copy
operations, but does affect consistency in the data update sequence. In the example in
Figure 17 (page 59), if you remove journal group 1 from the secondary EXCTG, the remote
copy operation from primary subsystem 1 to secondary subsystem 1 will continue. However,
consistency in the data update sequence will only be maintained between the primary
subsystems 2 and 3 and secondary subsystems 2 and 3.
Figure 17 Example 1: Remote Copy Operations Among Three Primary Storage Systems and
Three Secondary Storage Systems
• Guaranteed consistency of data update sequence:
URz restores journal data to secondary data volumes by taking the following steps. The
following procedure guarantees consistency of data update sequence within an extended
consistency group:
1. URz checks the extended consistency group for the time stamps of all journal data that
have not been restored to secondary data volumes, and then identifies the latest time
stamp for each journal group.
In the example shown in Figure 18 (page 60), the latest time stamp for each journal group
is as follows:
◦ In Journal group 1, the latest time stamp is 15:00.
◦ In Journal group 2, the latest time stamp is 15:02.
Using More Than One Primary and Secondary Storage System for Remote Console 59