HP XP P9500 Storage - Manual (Page 41)

If Business Copy pair relationships exist in the same parity group, host I/O responses might not
be improved.
FC Ext. Slower Copy1 Option
The FC Ext. Slower Copy1 option is used to prioritize host I/O response over background copying
processing of Compatible FlashCopy relationships. When the FC Ext. Slower Copy1 option is in
effect and the MP operating ratio of the MP blade exceeds 65%, background copy operations are
suppressed, and consequently host I/O response improves.
When background copying processing of Compatible FlashCopy is suppressed by the FC Ext.
Slower Copy1 option, the time taken for background copying increases.
CAUTION: If the FC Ext. Slower Copy2 option is in effect, the FC Ext. Slower Copy1 option
becomes invalid.
FC Ext. Slower Copy2 Option
The FC Ext. Slower Copy2 option is used to prioritize host I/O response over background copying
processing time of Compatible FlashCopy relationships. When the FC Ext. Slower Copy2 option
is in effect and the MP operating ratio of the MP blade exceeds 50%, background copy operations
are suppressed, and consequently host I/O response improves.
When background copying processing of Compatible FlashCopy is suppressed by the FC Ext.
Slower Copy2 option, the time taken for background copying increases.
CAUTION: If the FC Ext. Slower Copy2 option is in effect, the FC Ext. Slower Copy1 option
becomes invalid.
Cautions on turning off the power while using Compatible FlashCopy
This section describes what occurs if you power off the storage system during Compatible FlashCopy
operations and then power on the storage system later. What occurs depends on the status of the
shared memory when powering on the storage system:
WARNING! 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 that are in COPY mode,
background copying automatically restarts when you power on the storage system.
If data on the shared memory is volatilized and lost:
If relationships exist before you power off the storage system, the T-VOLs become blocked and
inaccessible from hosts when you power on the storage system again. The reason for making the
T-VOLs inaccessible is to prevent access to inconsistent data. To restore the T-VOLs to normal status,
force the restoration of 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, it is feared that data in the T-VOL is not normal. Therefore, delete data in the T-VOL
or initialize the T-VOL.
FC Ext. Slower Copy1 Option 41