HP StorageWorks XP Remote Web Console Software - Manual (Page 17)

I/O operation
: SMPL status
: COPY(PD) status
: PAIR status
: Time flow
Figure 3 Change of Pair Status When You Create a Pair
Before the initial copy operation, the status of a pair is SMPL. The status of the pair is COPY(PD) (PD
= pending) while the initial copy operation is in progress. The status changes to PAIR when the initial
copy is complete.
Since a P-VOL remains available to all hosts for read and write I/Os during the initial copy operation, the
P-VOL might be updated during the operation. Therefore, when the status of the pair changes to PAIR after
the initial copy operation is complete, the update copy operations take place and the differential data of
the P-VOL is copied to the S-VOL. As write I/Os are performed on a duplex P-VOL, the storage system
stores the differential bitmap, and then performs update copy operations periodically based on the amount
of differential data present on the P-VOL, as well as the elapsed time between update copy operations.
Figure 4 on page 18 illustrates an update copy operation in a Business Copy pair with only one S-VOL.
S-VOL P-VOL
PAIR
S-VOL P-VOL
COPY(PD)
SMPL
S-VOL P-VOL
Host
Initial Copy
Legend
XP24000 Business Copy Software User's Guide 17