HP XP7 Storage - Manual (Page 40)

Priority is determined within the range of the number of initial copy operations performed at the
same time. Therefore, until the first initial copy operations complying with the order set by Priority
are completed, the additional initial copy operations are not started.
Consistency group planning
Consistency groups allow you to perform one operation on all pairs in the group. Consistency
groups also ensure that all pairs are managed in a consistent status.
You determine which pairs to include in a particular consistency group. This is based on business
criteria for keeping status consistent across a group of pairs, and for performing specific operations
at the same time on the group.
•
A consistency group can consist of the pairs in one primary and one secondary XP7, or pairs
in multiple primary and secondary XP7s.
•
Both Cnt Ac-S and Cnt Ac-S Z pairs can belong to the same consistency group.
Consistency group for pairs in one primary and one secondary XP7
Cnt Ac-S and Cnt Ac-S Z pairs between one primary and secondary system can be placed in the
same consistency group, as shown in the following figure.
Figure notes:
•
Cnt Ac-S pairs are assigned to a consistency group using RAID Manager.
Cnt Ac-S Z pairs are assigned to a consistency group using Business Continuity Manager
(BCM).
•
Open and mainframe volumes (P-VOLs/P-VOLs) receive I/O requests from their applications
at the primary (main) site, and data in the volumes is updated.
•
Cnt Ac-S or Cnt Ac-S Z runs copy operations in the consistency group.
Consistency group for pairs in multiple primary and secondary systems
Cnt Ac-S and Cnt Ac-S Z pairs in multiple primary and secondary systems can be placed in the
same consistency group. A maximum of four storage system pairings can be placed in the same
consistency group.
40 Planning for Continuous Access Synchronous Z