HP StorageWorks XP24000 for FlashCopy Mirroring Software User's Guide (T5240-96001, June 2007)

Table 10 Additional Shared Memory for Differential Tables
Additional Shared Memor y
forVersion 1orVersion 2
Num. of
Differential Tables
Num. of Pair Tables Num. of Volumes
in
Subsystem
No additional shared memory
for Version 1
0 0
1,024
Additional shared memory for
Version 1 is installed
26,176 8,192
16,384
Additional shared memory for
Version 2 is installed
Extension 1
57,600 8,192 16,384
Extension 2 104,768 16,384 65,536
Extension 3
146,688 16,384
131,072
Extension 4
209,600
16,384
131,072
Notes:
• To install additional shared memor y for differential tables, call HP technical support.
• Even if you install additional shared memory for differential tables and pair tables, the
maximum number of relationships is half of the total number of volumes in the subsystem (see
Table 10 on page 24). For example, if additional shared memory for Version 1 is installed
(second
line in Table 10 on page 24) and the S-VOLs and T-VOLs are in a one-to-one relationship,
you can establish up to 8,192 relationships. However, note that in the case of Extension 2
through E xtension 4, the maximum number of relationships is 16,384, regardless of the total
number of volumes in the subsystem.
To calculate the maximum number of Version 1 relationships, firstyou need to calculatehow many
differential tables and pair tables are required to establish Version 1 relationships, and then compare the
result with the number of differential tables and pair tables in the whole storage system. Note that in
addition to Version 1, the following program products will also use differential tables and pair tables:
• Program products using differential tables
• HPStorageWorksXPBusiness CopySoftware
• ShadowImage for Mainframe
•Version 2
•Auto LUN
• HPStorageWorksXPSnapshot
• Program products using pair tables
•Business Copy
• ShadowImage for Mainframe
•Auto LUN
If Version 1 and these p rogram products are used in the same storage system, the number that is
deducted the number of differential tables and pair tables used by the pairs (migration plans in case
of
Auto LU N) of the program products shown above from the number of differential tables and pair
tables in the whole storage system will be the number of available differential tables and pair tables
for Version 1 relationships.
For information about how to calculate the number of differential tables and pair tables that are required
for Business Copy, see the HP StorageWorks XP24000 Business Copy Software User's Guide.For
ShadowImage for Mainframe, see the Hitachi ShadowImage for z /OS User's Guide.Also, see the HP
StorageWorks XP24000 Auto LUN Software User's Guide to calculate the numb er of differential tables
and pair tables that are required for Auto LUN, and see the HP StorageWorks XP24000 S napshot User’s
Guide to calculate the number of differential tables that are required for XP Snapsho t.
Assuming that only Version 1 uses differential tables and pair tables, this section describes how to
calculate the numb er of differential tables and pair tables required for one Version 1 relationship, and
24
Preparing for V ersion 1 Operations