HP XP Continuous Access Software - Manual (Page 48)

Table 15 Relationship Between Additional Shared Memory and Total Number of Bitmap Areas
in the Storage System
Total Number of Bitmap Areas in the
Storage System Additional Shared Memory for XP Continuous Access Journal
0 No additional shared memory for XP Continuous Access Journal
7,424 Additional shared memory for XP Continuous Access Journal is installed
16,384 Extension 1
32,768 Extension 2
44,256 Extension 3 (available only for XP24000 Disk Array)
65,536 Extension 4 (available only for XP24000 Disk Array)
Use the following formula to calculate the maximum possible number of pairs that can be
created on the basis of the number of bitmap areas described in
Table 15 (page 48) and the
required number of bitmap areas you calculated:
The maximum number of pairs = ( Number of bitmap areas required number of bitmap
areas )
The … symbols around a value indicate that the value should be rounded down to the nearest
integer.
If the calculated maximum number of pairs exceeds 32,768, the actual maximum number of
pairs is limited to 32,768.
The capacity of OPEN-V is variable. To get the maximum number of pairs of OPEN-V, calculate
the number by using the formula.
Caution: The bitmap areas that are used for XP Continuous Access Journal are also used for
Universal Replicator for Mainframe, XP Continuous Access, and TrueCopy for Mainframe. If
you use XP Continuous Access Journal with Universal Replicator for Mainframe, XP Continuous
Access, and TrueCopy for Mainframe, use the total number of each pair to calculate the
maximum number of pairs. In addition, if XP Continuous Access Journal and XP Continuous
Access share the same volume, use the total number of both pairs even if the shared volume
is primary or secondary.
Journal Groups
The XP Continuous Access Journal journal groups have the following requirements:
•
Each XP Continuous Access Journal pair must be assigned to only one journal group.
Table 16 (page 49) shows the specifications for journal groups.
48 Preparing for XP Continuous Access Journal Operations