HP XP Business Copy Software - Manual (Page 32)

32 Business Copy XP (BC) for the XP128/XP1024
Cautions on switching off the power supply
To switch off the power supply of the disk array during BC operations, make sure to:
• Complete copying for the BC pair in COPY(SP) or PSUS(SP) status first to change the pair status from
COPY(SP) or PSUS(SP) to PSUS, and then switch off the power supply. IF shared memory is volatilized
when you switch on the power supply again, the pair in COPY(SP) or PSUS(SP) status changes to PSUE.
• 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 supply 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
consistency rate is 0%, and the entire volume is copied to the secondary volume when you perform
the pairresync operation.
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.
• Command View XP management station (user-supplied Windows®-based PC).
• BC license key installed.
Preparing for BC operations
To ensure that you and your disk arrays are ready for BC operations, perform the following tasks:
• BC operations affect I/O performance of the disk array because of copy operations to the S-VOLs. If
you have not already done so, consider the relative importance of the disk array’s I/O performance
and the BC backup copies. For example, assigning three S-VOLs to each P-VOL takes more resources
than assigning one or two. You can also use the copy pace option to control the impact of BC initial
copy operations. Using a slower copy pace minimizes the impact of BC operations on I/O
performance, while a faster copy pace produces copies more quickly, but may affect I/O performance.
• If you are using more than one disk array data management feature (such as BC, Continuous Access XP ,
or Cache LUN XP) at the same time in the same disk array, contact your HP account support
COPY(RS-R) The disk array does not accept write I/Os for COPY(RS-R) S-VOLs. When
a split pair is resynchronized in reverse or quick restore mode, the disk
array copies only the S-VOL differential data to the P-VOL. No update
copy operations are performed during the reverse or quick restore
pairresync operation.
Read only.
PSUE The disk array continues accepting read and write I/Os for a PSUE
(suspended) P-VOL, but does not perform update copy operations for a
PSUE S-VOL. The disk array marks the entire P-VOL track map as
difference data, so the entire P-VOL is copied to the S-VOL when the
PSUE pair is resumed. Use the pairresync command to resume a PSUE
pair.
Read only.
Table 11 BC pair status conditions (continued)
Pair Status Description S-VOL Access