HP XP P9500 Storage - Manual (Page 25)

Figure 3 Overview of volume operation
Copy groups
A copy group is a set of copy pairs that have the same copy type (Business Copy Z, Continuous
Access Synchronous Z, TrueCopy Asynchronous for Mainframe or Continuous Access Journal Z),
and is designated a copy group ID for identification. An operation performed on a copy group is
performed on all of the copy pairs within that copy group.
To define a copy group and assign a copy group ID, see “Defining a copy group” (page 646) .
Consistency groups
A consistency group is a copy group recognized by a storage system.
A consistency group updates the S-VOLs in the same order that data was put onto the P-VOLs. The
data on an S-VOL is guaranteed to be identical to the data on a P-VOL at consistency times.
Therefore, data at the secondary site can be used to recover the data at the primary site. This is
called preserving consistency. The consistency of updates is assured throughout the entire consistency
group. For details on consistency time, see
“Consistency times and consistency delta values”
(page 32) .
How to preserve consistency
To define a copy group as a consistency group, a consistency group ID can be specified when
the copy group is defined.
Table 1 (page 26) lists the methods for preserving consistency for each consistency group copy
type.
Grouping to simplify volume operations 25