HP StorageWorks XP Remote Web Console Software User Manual
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this point, two kinds of information, the time stamp information issued from RAID Manager
and the sequence number indicating the write order, are added to the journal data.
4.
The journal copy function allows XP Continuous Access Journal to copy the journal data in
the primary journal volume to the paired restore journal volume. Journal copying is performed
asynchronously with journal obtaining.
5.
The following time stamps are reported to the primary storage system:
•
The latest time stamp of the data that is copied to the secondary storage system
•
The time stamp of the restored data
6.
RAID Manager issues the order to obtain the time stamp information, and the secondary
storage system reports the forwarded time stamp.
7.
Among the time stamp data reported by the multiple storage systems, RAID Manager selects
the time stamp data that is most appropriate for restoring, and issues the time stamp for
restoring.
8.
The primary storage system forwards the time stamp data received from RAID Manager.
9.
The secondary storage system restores the data of up to the newer than and the nearest time
stamp that are sent from the primary storage system.
Hardware Configuration for Using Multiple Primary and Secondary Storage Systems
HP recommends that RAID Manager is installed on the host in both the primary and remote sites
when the system consists of multiple primary and secondary storage systems. Remote Web Console
computers must be installed in both of these sites. For information about using RAID Manager, see
the HP StorageWorks RAID Manager User 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.
below shows the conditions of the consistency group of the system that consists
of multiple primary and secondary storage systems.
Table 18 Conditions of Consistency Group (When the System Consists of Multiple Primary and
Secondary Storage Systems)
Condition
Item
Up to four journal groups can be registered in one
consistency group. If there are four storage systems, you
must create one journal group for each storage system.
Number of available journal groups
Up to 8,192 pairs, the total number of pairs registered in
the journal groups in one consistency group, can be
Number of available pairs
registered. However, HP recommends that you register up
to 4,096 pairs.
Notice of the Error Suspension Between the Journal Groups
When the system consists of multiple primary and secondary storage systems, and if an error occurs
in one journal group, the error affects other journal groups and all journal groups become suspended
by the error. An error occurred in a journal group is noticed by all other journal groups only when
the time stamps are issued to all journal groups to run the system while maintaining the data
consistency. The conditions are as follows:
•
The LAN connections between the RAID Manager and all primary storage systems is normal.
•
The status of the failed journal group is PJSE or PJSF.
•
At least one journal group in the consistency group is in normal status.
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Preparing for XP Continuous Access Journal Operations