HP XP7 Storage - Manual (Page 12)

Dataset copying can be performed when:
•
The position of the copy source extent is different from the position of the copy target extent
and both extents are on the same volume.
•
The copy source extent and the copy target extent are on different volumes.
•
The copy source extent and the copy target extent do not overlap when they are on the same
volume.
•
The data in a single source extent is to be copied simultaneously to multiple target extents.
•
Volume copying is also being performed using the same source volume.
•
Two source extents overlap, or one of them is part of the other (see the following figure),
provided that the number of overlapping extents in each overlapped area is not more than
16 extents.
Figure 6 Overlap of copy source extents
Dataset copying cannot be performed when:
•
Any one of the copy target extents overlaps another copy target extent.
•
Any one of the copy target extents overlaps a copy source extent.
•
A copy target extent that already has a relationship established is used to establish a new
relationship in which the copy source or target extent overlaps the target extent.
•
A copy source extent that already has a relationship established is used to establish a new
relationship with a copy target extent that overlaps the original copy source extent.
Using Consistency Groups for Dataset Copies that Span Volumes
If you use a consistency group, you may create copied data that keeps consistency even when the
source data depends on each other and is stored on multiple volumes.
The following figures show examples of using a consistency group:
Figure 7 Using Consistency Groups with Compatible FlashCopy: Copying data stored over multiple
volumes
12 About Compatible FlashCopy