HP XP Business Copy Software - Manual (Page 21)

Business Copy XP user guide for the XP10000/XP12000 21
• = 13,652 when additional shared memory for differential tables is not installed.
• = 30,718 when additional shared memory for differential tables is installed.
For example, if you create 10 pairs of LUSE volumes consisting of three OPEN-3 volumes, use the following
equation: .
Since 30 is less than 13,652, 10 pairs of LUSE volumes consisting of three OPEN-3 volumes can be
created.
NOTE: When the emulation type is OPEN-3, and the capacity of the volume is 2,403,360 KB, the
number of differential tables required for a pair is 1.
BC operations
Set reserve attribute operation
This operation reserves a volume so it can be used as a BC S-VOL. Reserved volumes can only be used as
BC S-VOLs. The disk array rejects all write operations to reserved volumes (unless in split (PSUS) status).
You can reserve up to 4,095 volumes in one disk array. Use the Set Reserve Attribute window (see ” Setting
reserve attributes ” on page 57) to reserve volumes for use as BC S-VOLs.
A volume might be reserved for BC to ensure that a server does not mount it before BC can use it in a pair.
BC cannot use a volume as an S-VOL if it is being used by a server.
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 ” on page 58) 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) ” on page 58) 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.
β ( )
β ( )
1 3 Ч ( ) 10 Ч 30 13,652 ≤ =