Host i/o performance option, Host i/o – HP XP Business Copy Software User Manual
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shows the state of the T-VOL after the quick restore operation with or without
the Swap&Freeze option.
Figure 9 Quick Restore Operation With or Without Swap&Freeze Option
The Quick Restore pairresync operation on a pair which status is split exchanges the data in the
S-VOL and the T-VOL of the pair. If you use Swap&Freeze option when performing the Quick
Restore pairresync operation, the update copy operation will not take place after the Quick Restore
pairresync operation is complete. Therefore, the data of the S-VOL and the T-VOL is kept exchanged.
If you do not use Swap&Freeze option when performing the Quick Restore pairresync operation,
the update copy operation will take place after the Quick Restore pairresync operation is complete,
and the data in the S-VOL overwrites the T-VOL.
Host I/O Performance Option
The Host I/O Performance option is used to improve host I/O responses over SIz copying processing
time. When the Host I/O Performance option is in effect, the storage system suppresses execution
of SIz copying processing, and consequently host I/O responses improve.
When SIz copying processing is suppressed by the Host I/O Performance option, the time taken
for copying increases. Also, if ShadowImage for Mainframe pairs exist, host I/O responses might
not be improved. In this case, set the Host I/O Performance option for ShadowImage for Mainframe
as well.
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About ShadowImage for Mainframe Operations