Relationship expansion, Copying data by using consistency group – HP XP Business Copy Software User Manual
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Relationship Expansion
CAUTION:
In order to enable or disable the relationship expansion function, you must delete all
FlashCopy Mirror Version 2 relationships and Copy-on-Write Snapshot pairs beforehand.
The relationship expansion function increases the maximum number of the relationships FlashCopy Mirror
Version 2 can establish. Normally, FlashCopy Mirror Version 2 can establish up to 32,768 relationships,
but if you use the relation expansion function, FlashCopy Mirror Version 2 will be able to establish up to
1,048,575 relationship. However, note that if the copy solutions other than FlashCopy Mirror Version 2 are
being used in the disk subsystem, the number of the relationships FlashCopy Mirror Version 2 can
establish may decrease. For details, see ”
Maximum Number of FlashCopy Mirror Version 2 Pairs
Even if you use the relationship expansion function, you cannot increase the maximum number of volume
pairs. When the emulation type is 3390-1, 3390-2, 3390-3, or 3390-3R, the maximum number of volume
pairs that FlashCopy Mirror Version 2 can create is 8,192 (8,192 S-VOLs and 8,192 T-VOLs).
When the emulation type is 3390-M, the maximum number of volume pairs that FlashCopy Mirror Version
2 can create is usually 903 (903 S-VOLs and 903 T-VOLs). However, FlashCopy Mirror Version 2 can
create more than 903 volume pairs by using 3390-M volumes, depending on the number of cylinders. For
details, see
Copying Data by Using Consistency Group
If you use a consistency group, you may create copied data that keeps consistency even when the source
data depends on each other and are stored in multiple volumes. The following figures show examples of
using a consistency group (see
)
.
Figure 51
Ex. Using Consist. Group w/FlashCopy(R) Mirror Ver. 2: Copying Data Stored over Mult. Vols.
Incremental
FlashCopy
Multi relationship
NO
NO
NO
OK
Incremental
FlashCopy
NOCOPY mode
NO
NO
OK
OK
COPY mode
OK
OK
OK
OK
Table 46
Compatibility between FlashCopy Mirror Version 2 and User Interface Functions (continued)
Function
User Interface
TSO
DFSMSdss
ICKDSF
ANTRQST
Macro