HP XP Business Copy Software - Manual (Page 21)

NOTE:
BC leaf volumes (L2 cascade pair) also function as S-VOLs and must be reserved prior to being
assigned to an L2 cascade pair.
Reset reserve attribute operation
This operation unreserves a volume so it can be mounted and accessed by all hosts. After you reset
the reserve attribute, the disk array accepts all subsequent I/O operations to the volume. Use the Reset
Reserve Attribute window (see
Resetting reserve attributes ) to unreserve volumes.
Paircreate operation
This operation establishes the new BC pairs. The volume that will be the P-VOL must be in the SMPL
(simplex) state, and the volume that will be the S-VOL must be in the SMPL state before being added
to a BC pair.
NOTE:
You can reserve the S-VOL before creating a pair, but you can also create a pair with an unreserved
S-VOL. Use the Paircreate window (see
Creating BC pairs (Paircreate) to create new BC volume pairs.
Initial copy operation
This operation occurs when you create a new volume pair (see Figure 2 ). The BC initial copy operation
copies all data on the P-VOL to the associated S-VOL. The P-VOL remains available to all hosts for
read and write I/Os throughout the initial copy operation. After the initial copy is complete, the update
copy operation duplicates write operations performed on the P-VOL during the initial copy operation
at the S-VOL.
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. Write operations performed on the P-VOL during the initial copy operation are
duplicated at the S-VOL by update copy operations after the initial copy is complete.
CAUTION:
Even if a copy operation is completed without any host I/O, the data in the P-VOL and S-VOL may
not be identical. Whether the P-VOL and the S-VOL have the same data depends on the condition
of the disk array. To make the P-VOL and S-VOL data the same, split the pair and make the pair
status PSUS.
NOTE:
When creating pairs, you can select the pace for the initial copy operation: slower, medium, and
faster. The slower pace minimizes the impact of BC operations on disk array I/O performance, while
the faster pace completes the initial copy operation as quickly as possible.
XP Business Copy User Guide 21