HP StorageWorks XP Remote Web Console Software - Manual (Page 76)

• The consistency time of an extended consistency group is the latest time stamp of the restored
data in the group in which consistency is guaranteed.
In the example shown in
Figure 18 on page 75, the consistency time of the extended consistency
group is 15:00.
• The consistency time of a journal group is the latest time stamp of the restored data.
In the example shown in Figure 18 on page 75, the consistency times of journal groups 1 to 4
are as follows.
• The consistency time of Journal group 1 is 15:00.
• The consistency time of Journal group 2 is 14:02.
• The consistency time of Journal group 3 is 14:03.
• The consistency time of Journal group 4 is 14:04.
• The consistency time of a data volume pair is the latest time stamp of the data that has been
restored when the pair becomes suspended.
In the example shown in
Figure 18 on page 75, if a pair in the journal group 1, 2, 3 or 4 is
suspended immediately after data are restored, the consistency time of the pair will be as follows.
• If a pair in Journal group 1 is suspended, the consistency time will be 15:00.
• If a pair in Journal group 2 is suspended, the consistency time will be 14:02.
• If a pair in Journal group 3 is suspended, the consistency time will be 14:03.
• If a pair in Journal group 4 is suspended, the consistency time will be 14:04.
If a failure occurs in a primary storage system and then you wish to recover from the failure, please
restore journal data with time stamps later than the consistency time of the extended consistency
group to secondary data volumes. For example, in the case described in Figure 18 on page 75,
the consistency time of the extended consistency group is 15:00, and therefore you must restore
the following data to secondary data volumes.
• Data with the time stamp 15:02 in journal group 2
• Data with the time stamp 15:03 in journal group 3
• Data with the time stamp 15:04 in journal group 4
If a failure occurs in a secondary storage system and then you wish to recover from the failure,
please compare the consistency times of all journal groups in the extended consistency group, and
then identify the oldest consistency time. Next, please restore all data with time stamps later than
the oldest consistency time, to the secondary data volume. For example, in the case described in
Figure 18 on page 75, the consistency time of journal group 2 is the oldest among journal groups
1 to 4. Since the consistency time of journal group 2 is 14:02, you must restore the following data
to secondary data volumes.
• Data with the time stamp 15:00 in journal group 1
• Data with the time stamp 15:02 in journal group 2
• Data with the time stamp 14:03, and data with the time stamp 15:03 in journal group 3
• Data with the time stamp 14:04, and data with the time stamp 15:04 in journal group 4
Connections Among Secondary Storage Systems
If you use more than one primary subsystem and more than one secondary subsystem, you must establish
connections among the secondary subsystems. To do this, you must configure paths and ports. Also, you
must create remote command devices by using Universal Volume Manager.
76 Preparing for Universal Replicator z/OS Operations