To Avoid Any Performance Impact Due To The Quick Restore Operation; Requirements For Reverse Or Quick Restore Pairresync Operations - HP StorageWorks XP10000 User Manual

CAUTION: During a quick restore operation, the RAID levels, HDD types, and Cache LUN settings of the
P-VOL and S-VOL are exchanged. For example, if the P-VOL has a RAID-1 level and the S-VOL has a
RAID-5 level, the quick restore operation changes the P-VOL to RAID-5 and the S-VOL to RAID-1. This also
applies to RAID-6 volumes.

To avoid any performance impact due to the quick restore operation

1. Ensure that the P-VOL and S-VOL have the same RAID level and HDD type before performing the quick
restore operation. To restore the original RAID levels after a quick restore, stop host I/Os to the pair,
split the pair, perform the quick restore operation for that pair again, and restart host I/Os to the pair.
2. Because Cache LUN settings are exchanged during a quick restore operation, you must perform one of
the following operations. If you do not, the change of location of cache residence areas may cause I/O
performance to the Cache LUN data to be down.
• Set the same Cache LUN settings (locations) for the P-VOL and S-VOL before performing the quick
restore operation.
• Release the Cache LUN settings of the P-VOL and S-VOL before the quick restore operation, and
reset the Cache LUN settings of the P-VOL and S-VOL after the pair changes to PAIR status as a
result of the quick restore operation.
CAUTION: If you do not want the P-VOL and S-VOL to be resynchronized after the quick restore operation,
set the Swap&Freeze option before performing the quick restore operation (see
and "Setting BC
page 30
Table 9 shows the requirements for reverse and quick restore pairresync operations. If you perform these
operations on pairs that do not fulfill the requirements, the reverse copy or quick restore command is
rejected.
Table 9

Requirements for reverse or quick restore pairresync operations

Parameter
Pair status
Pair type
Shared BC/Continuous
Access XP volume
Shared BC/Continuous
Access XP Journal volume
NOTE: A Continuous Access XP Journal P-VOL means a Continuous Access XP Journal primary data
volume. A Continuous Access XP Journal S-VOL means a Continuous Access XP Journal secondary data
volume.
CAUTION: If a reverse or quick restore resync operation ends abnormally, or a Pairsplit-E (PSUE) is
requested during a reverse or quick restore resync operation, the status of other BC pairs sharing the same
P-VOL does not change.
options" on page 73).
Requirements
The specified pair must be in the PSUS state. All other pairs sharing the same P-VOL
as the specified pair must also be in the PSUS or PSUE state.
Whether you can execute a quick restore command for a pair consisting of
customized and normal volumes depends on the volume's emulation type.
If BC and Continuous Access XP pairs share the same volume, and the Continuous
Access XP pair is not suspended, you cannot perform reverse and quick restore
pairresync operations.
If the BC and Continuous Access XP Journal pairs share the same volume, and the
Continuous Access XP Journal pair is not suspended, you cannot perform the reverse
and quick restore pairresync operations.
Business Copy XP user guide for the XP10000/XP12000
"Swap&Freeze option" on
27