Hitachi ShadowImage for z/OS user guide (HIT9503-96004, June 2006)

100 ShadowImage for the XP1024/XP128/XP12000/XP10000

Table 46 shows the compatibility between the FlashCopy Mirror Version 2 functions and the user interface

functions.

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 Table 47

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)

Table 46 Compatibility between FlashCopy Mirror Version 2 and User Interface Functions

User Interface Function Functions

Volume

copying

Dataset

copying

COPY mode NO COPY

mode

DFSMSdss TSO Multiple relations Supported Supported Supported Supported

COPY mode Supported Supported Supported

1. Represents the case when the copy operation mode is changed from NOCOPY mode to COPY mode.

N/A

NOCOPY mode Supported Supported N/A N/A