HP StorageWorks XP Remote Web Console Software - Manual (Page 72)

processing time of relationships is not always the same, the processing time is not necessarily
doubled.
If XP Business Copy pairs or Version 1 relationships 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 the background copying
processing time of Version 2 relationships. When the FCv2 Slower Copy2 option is in effect, the
number of Version 2 relationships that can be copied simultaneously in the background will be
suppressed to one-quarter, and consequently host I/O responses improve.
The two options, FCv2 Slower Copy2 and FCv2 Slower Copy1, have the same function. The
difference between them is that FCv2 Slower Copy2 allows improved host I/O responses because
it suppresses more background copy operations than the FCv2 Slower Copy1 option.
CAUTION: If the FCv2 Slower Copy2 option is in effect, the FCv2 Slower Copy1 option becomes
invalid.
When background copying processing in Version 2 is suppressed by the FCv2 Slower Copy2
option, the time taken for processing increases. However, because the background copying
processing time of relationships is not always the same, the processing time will not necessarily
quadruple.
If XP Business Copy pairs or Version 1 relationships exist in the same parity group, host I/O
responses might not be improved.
Cautions on Turning Off the Power While Using Version 2
This section describes what happens if you power off the storage system during Version 2 operations
and later power on again. What occurs depends on the status of the shared memory when powering
on the storage system.
CAUTION: If data on the shared memory is volatilized and lost after the power turns on, problems
may occur during operations. To avoid possible problems, withdraw as many relationships as
possible before powering off the storage system.
•
If data on the shared memory is not volatilized and not lost:
The status before powering off will be maintained. As for the relationships in COPY mode,
background copying will automatically restart when you power on the storage system.
•
If data on the shared memory is volatilized and lost:
If relationships existed before the storage system was powered, the T-VOLs will become blocked
and inaccessible from the hosts when you power on the storage system. Thus, the host does
not access the inconsistent data in the T-VOLs. To restore the T-VOLs to normal status, force
the restoration of the LDEVs.
If the T-VOL is an external volume, the storage system may start normally and the T-VOL may
not become blocked even if data on the shared memory is lost. However, although the storage
system starts normally, data in the T-VOL may not be normal. Therefore, you should delete
data in the T-VOL or initialize the T-VOL.
Installing and Uninstalling Version 2
This section describes how to install and uninstall Version 2. To enable FlashCopy Version 2 to
function on the storage system, the Compatible FlashCopy feature and software must be installed
and enabled on the storage system. For details about the license operation, see the HP
StorageWorks XP24000/XP20000 Remote Web Console User Guide.
72 Preparing for Version 2 Operations