Hitachi ShadowImage for IBM z/OS User"s Guide (T5213-96002, June 2007)

2-18 About ShadowImage™ for IBM
®
z/OS
®
Operations
Hitachi ShadowImage™ for IBM
®
z/OS
®
User’s Guide
Table 2-2 Pair Status and Allowable Operations
Pair Status Operation
Simplex Pending Duplex SP-Pend V-Split Split Resync Resync-R Suspend
Add Pair OK NG NG NG NG NG NG NG NG
Split Pair OK OK OK NG NG NG NG NG NG
Suspend Pair NG OK OK OK OK OK OK OK NG
Resync Pair
(forward)
NG NG NG* NG OK OK NG* NG OK
Resync Pair
(backward)
NG NG NG NG NG OK NG NG NG
Delete Pair NG OK OK OK NG OK OK OK OK
Note*: If you try to resynchronize a pair in duplex or resync status by copying
data from the S-VOL to the T-VOL, the processing will end normally. However,
since actually no resynchronize processing will be performed, the pair status
does not change.
ShadowImage for z/OS Options
You can use the options in Table 2-3 for SIz operations.
Table 2-3 Types of ShadowImage for z/OS Options
Option Type Features Requirement
Swap&Freeze
Swap&Freeze option suppresses the
update copy. For details, see section
Swap&Freeze Option.
You must change the storage system setting
to allow the quick restore operation.
Host I/O
Performance
Host I/O Performance option suppresses
the copy operations by ShadowImage
for z/OS
®
. For details, see section Host
I/O Performance Option.
-
Copy Threshold
Copy Threshold option temporarily stops
the copy operation of ShadowImage for
z/OS. For details, see section Copy
Threshold Option.
-
Note: Available option types depend on the USP V storage system settings.
Swap&Freeze Option
The Swap&Freeze option allows the S-VOLs of an SIz pair to remain
unchanged after the quick restore operation. If the quick restore operation is
performed on an SIz pair with the Swap&Freeze option, update copy
operations are suppressed, and thus are not performed for pairs in the duplex
status after the quick restore operation. If the quick restore operation is
performed without the Swap&Freeze option, the S-VOL and T-VOL are
resynchronized when update copy operations are performed for pairs in the
duplex status.