HP XP Business Copy Software - Manual (Page 30)

30 ShadowImage for the XP1024/XP128/XP12000/XP10000/SVS 200
The Quick Restore pairresync operation on a pair with split status exchanges data in the pair’s S-VOL and
T-VOL. If you use the Swap&Freeze option when performing the Quick Restore pairresync operation, the
update copy operation does not take place after the Quick Restore pairresync operation is complete.
Therefore, data on the S-VOL and T-VOL is kept exchanged. If you do not use the Swap&Freeze option
when performing the Quick Restore pairresync operation, the update copy operation takes place after the
Quick Restore pairresync operation is complete, and data on the S-VOL overwrites the T-VOL.
Host I/O Performance Option
The Host I/O Performance option improves host I/O responses over SI390 copying processing time. When
the Host I/O Performance option is used, the disk array suppresses execution of SI390 copying processing,
and consequently the host I/O responses improve.
When SI390 copying processing is suppressed by the Host I/O Performance option, the time taken for
copying increases. Also, if BC pairs exist, host I/O responses might not be faster. In this case, set the Host
I/O Performance option for BC as well.
FCv2 Slower Copy1 Option
The FCv2 Slower Copy1 option is used to improve host I/O responses over copying processing time of
FlashCopy Mirror Version 2 pairs. When the FCv2 Slower Copy1 option is in effect, the number of the
FlashCopy Mirror Version 2 pairs that can be copied simultaneously will be suppressed to half, and
consequently host I/O responses improve.
CAUTION: If the FCv2 Slower Copy2 option is in effect, FCv2 Slower Copy1 option becomes invalid.
NOTE:
•
When copying processing of FlashCopy Mirror Version 2 is suppressed by the FCv2 Slower Copy1
option, the time taken for copying increases. However, since the copying processing time of pairs is not
always same, note that the copying processing time will not be necessarily doubled.
• If ShadowImage pairs or FlashCopy Mirror Version 2 pairs exist in the same parity group, host I/O
responses might not be improved.
Fcv2 Slower Copy2 Option
The FCv2 Slower Copy2 option is used to improve host I/O responses over copying processing time of
FlashCopy Mirror Version 2 pairs. When the FCv2 Slower Copy2 option is in effect, the number of the
FlashCopy Mirror Version 2 pairs that can be copied simultaneously will be suppressed to one-quarter, and
consequently host I/O responses improve.
The FCv2 Slower Copy2 option and the FCv2 Slower Copy1 option basically have same function. The
difference between these two options is that the you can more improve host I/O responses by using the
FCv2 Slower Copy2 option than by using the FCv2 Slower Copy1 option. This happens since the FCv2
Slower Copy2 option suppresses more copy operations compared to the FCv2 Slower Copy1 option.
CAUTION: If the FCv2 Slower Copy2 option is in effect, FCv2 Slower Copy1 option becomes invalid.
NOTE:
•
When copying processing of FlashCopy Mirror Version 2 is suppressed by the FCv2 Slower Copy2
option, the time taken for copying increases. However, since the copying processing time of pairs is not
always same, note that the copying processing time will not necessarily quadruple.
• If ShadowImage pairs or FlashCopy Mirror Version 2 pairs exist in the same parity group, host I/O
responses might not be improved.