HP XP24000/XP20000 for FlashCopy Mirroring Software User Guide (T5240-96012, November 2011)

Table 9 Additional Shared Memory for Differential Tables
Number of Volumes in
Storage System
Number of Pair TablesNumber of Differential
Tables
Additional Shared Memory for Version 1 or
Version 2
1,02400No additional shared memory for Version 1
16,3848,19226,176Additional shared memory for Version 1 is
installed
16,3848,19257,600Additional shared memory for Version 2 is
installed
Extension 1
65,53616,384104,768Extension 2
131,07216,384146,688Extension 3
1
131,07216,384209,600Extension 4
1
1
Extension 3 and Extension 4 can be used only in an XP24000 disk array.
NOTE:
• To install additional shared memory 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 storage system (see
(page 15)). For example, if additional shared memory for Version 1 is installed (second line
in (page 15)) 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 Extension
4, the maximum number of relationships is 16,384, regardless of the total number of volumes
in the storage system.
To calculate the maximum number of Version 1 relationships, first you need to calculate how 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 entire storage system.
In addition to Version 1, the following program products will also use differential tables and pair
tables:
• Program products using differential tables
HP XP Business Copy Software◦
◦ ShadowImage for Mainframe
◦ XP for FlashCopy Mirroring V2 Software
◦ XP Auto LUN
◦ HP XP Snapshot Software
• Program products using pair tables
XP Business Copy◦
◦ ShadowImage for Mainframe
◦ XP Auto LUN
If Version 1 and the program products listed previously are used in the same storage system, the
number that is deducted from the number of differential tables and pair tables in the entire storage
system (migration plans in case of XP Auto LUN) 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 ShadowImage for Mainframe, see the Hitachi ShadowImage™ for Mainframe User
Calculating the Maximum Number of Version 1 Relationships 15