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

ShadowImage for z/OS user guide 137
Relationship Between Compatible Mirroring for IBM FlashCopy and Compatible
Mirroring for IBM FlashCopy Version 2
Table 61 Differences Between FlashCopy Mirror and FlashCopy Mirror Version 2
No. Compared item FlashCopy Mirror FlashCopy Mirror Version 2
1 Required software and
memory
ShadowImage for z/OS software
FlashCopy Mirror software
ShadowImage for z/OS software
FlashCopy Mirror Version 2 software
Additional shared memory may also
be necessary.
2 Requirement on the
capacity of the S-VOL
and T-VOL for volume
copy operation
S-VOL = T-VOL S-VOL = T-VOL
3 S-VOL/T-VOL LSS Can create pairs with only volumes in
the same LSS.
Can create pairs with volumes in the
same LSS or different LSS.
4 Range of extents Can create pairs with the entire source
and target volumes, or with the copy
source and target extents that located
at the same position on the source and
target volumes.
Can create pairs with the entire source
and target volumes, or with the copy
source and target extents located at the
same or different position on the source
and target volumes.
5 Unit used for pair
management
Pairs are managed by volume. Even
when multiple datasets on the same
volume are specified, the number of
pair is regarded as 1.
Pairs are managed by the specified
extents, or by volume when the entire
volume is specified. When multiple
datasets are specified on the same
volume, each dataset is regarded as a
pair.
6 Number of pairs
created with a source
1 pair can be created with 1 source
volume.
Maximum of 16 pairs can be created
with 1 source extent.
7 Requirements for
creating pairs
Pairs can be created with simplex SIz
volumes. It is also possible to create
pairs which specify split or duplex SIz
S-VOL or T-VOL as the source.
SIz S-VOL that already forms pair with
three T-VOLs cannot be specified as
S-VOL of a FlashCopy Mirror pair.
Pairs can be created with simplex SIz
volumes. It is also possible to create
pairs which specify split or duplex SIz
S-VOL or T-VOL as the source.
Up to 16 FlashCopy Mirror Version 2
pairs can be created by specifying the
SIz S-VOL that already forms pair with
three T-VOLs.
8 Using with other copy
solutions
FlashCopy Mirror pair can share the
volume with other copy solutions such
as SIz, TCz, XRC, or Concurrent Copy.
FlashCopy Mirror Version 2 pair can
share the volume only with SIz.
9 DFSMSdss command COPYFULL command is used to create
a FlashCopy Mirror pair with the entire
volume.
COPYFULL command is used to create
a FlashCopy Mirror Version 2 pair with
the entire volume.
COPY DS command is used to create a
FlashCopy Mirror Version 2 pair with
specified dataset.
10 When DFSMSdss
command is issued
again during
background copy
operation
If the copy operation is required for the
FlashCopy Mirror volume during the
copying process, the normal copy
operation will be performed via the
host.
If the copy operation is required for the
FlashCopy Mirror Version 2 volume
during the copying process, DFSMSdss
command will withdraw the pair, and
create the pair again, and then
perform the copy operation.