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NOTE:
If the shared memory is volatilized when you switch on the power supply again, the pair in the
COPY(SP) or PSUS(SP) status changes to PSUE.
NOTE:
If the status of only a part of the pairs in the same consistency group is changed, the processing
of At-Time Split function may not resume when you switch on the power supply, and the status of
some pairs may remain unchanged.
• Establish a timetable for BC copying operations. If shared memory is volatilized when you switch
on the power supply again, the following conditions occur:
• If the BC pair was in COPY(PD) or COPY(SP) status, data already copied becomes target data
to be copied after the power supply is switched back on. Even if there is no host I/O, the data
consistency
rate does not reach 100% when the BC pair status changes to PAIR. When the BC
pair status changes to PAIR, target data is copied to the secondary volume.
• If the BC pair was in PAIR status, data already copied becomes target data to be copied after
the power su
pply is switched back on. In this case, the data consistency rate is 0%, and
target data is copied to the S-VOL.
• If the BC pair was in PSUS status, the entire volume becomes differential data. In this case,
the data con
sistencyrateis0%,andtheentirevolumeiscopiedtothesecondaryvolume
when you perform the pairresync operation.
Cautions on using the XP10000
The XP10000 has a fewer processors than the XP12000. Therefore, BC copy processing sometimes takes
a long time and host I/O performance may degrade. Consider the following:
• Copy processing
When you use BC on the XP10000, copy processing time (such as pair creation, pair split, and
pair resynchronization) might take longer compared to when you use BC on the XP12000. Copy
processing time changes according to the number of pairs, and sometimes the XP10000 requires two
to eight times the copy processing time compared to the XP12000.
• Host I/O performance
Since BC copy processing uses processors, host I/O performance might degrade during copy
processing. The number of processors in the XP10000 is small, therefore, when you use the XP10000,
the impact of copy processing on host I/O performance is larger than when you use the XP12000. To
mitigate host I/O performance degradation, reduce the copy pace or use the Host I/O Performance
option.
For more information about specifying the copy pace, see Copy Pace list. For more information about
theHostI/OPerformanceoption,seeHost I/O Performance option.
Preparing for BC operations
System requirements
BC operations involve the disk array containing the primary and secondary volumes and the licensed BC
feature enabled on the Command View XP management station or XP Remote Web Console. System
requirements for BC are:
• Disk array hardware, microcode, and software required for BC operations must be installed
and enabled.
Business Copy XP user guide
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