HP XP Continuous Access Software - Manual (Page 90)

NOTE: Just after creating the XP Continuous Access Journal pair for delta resync operation
(or if the failure occurred at the primary site right after the recovery of XP Continuous Access
Synchronous or XP Continuous Access Journal pair), only a part of the differential data between
the primary and secondary data volume may be stored in the master journal group.
•
The XP Continuous Access Journal pair(s) that are to be used for the delta resync operation
has the same number of secondary volumes as the XP Continuous Access Journal pairs that
are between the primary and tertiary sites.
•
The path between the primary and secondary sites to which the XP Continuous Access Journal
pair for delta resync operation belongs is available.
•
After creating the XP Continuous Access Journal pair for delta resync operation or performing
delta resync operation, update the primary site longer than 5 minutes after the status of the
XP Continuous Access Journal pair and the XP Continuous Access pair turned PAIR status.
If the delta resync operation that uses remote command devices is to be performed, you can
execute the delta resync operation directly after the primary site is updated.
The delta resync operation is also performed in the following cases:
◦ When the XP Continuous Access Journal pair status changes to HOLD after the delta
resync operation.
◦ When you re-create the XP Continuous Access Journal pair for delta resync operation
when recovering the primary site.
When the pair recovery operation performed on a suspended XP Continuous Access pair or
XP Continuous Access Journal pair, update the primary site longer than 5 minutes after the
status of the XP Continuous Access Journal pair and XP Continuous Access pair turned PAIR
status.
If the delta resync operation that uses remote command devices is to be performed, you can
execute the delta resync operation directly after the primary site is updated.
If any XP Continuous Access Journal pair in the journal group does not meet the above requirements,
an error occurs and delta resync operation will fail, even if the specified XP Continuous Access
Journal pair meets the requirements.
In the following cases, the delta resync operation will not be performed because the necessary
journal data does not exist:
•
When, after creating the XP Continuous Access Journal pair, the primary data volume in the
XP Continuous Access Journal pair for the delta resync operation is updated, but the XP
Continuous Access Journal primary data volumes (also used as XP Continuous Access
Synchronous primary data volumes) are not updated in the primary site.
•
When the volumes in the primary site are updated after splitting the XP Continuous Access
Synchronous pair.
•
When the secondary data volume is updated after splitting the XP Continuous Access Journal
pair.
•
When, after splitting the XP Continuous Access Journal pair and as a result of the update of
the primary data volume, the capacity of the journal data exceeds 80% of the journal volume
in the XP Continuous Access Synchronous secondary site.
•
When the primary data volume in the XP Continuous Access Journal pair for the delta resync
operation is updated, and then the capacity of the journal data exceeds 80% of the journal
volume in the primary site of the XP Continuous Access Journal pair for the delta resync
operation.
90 Preparing for XP Continuous Access Journal Operations