HP StorageWorks XP24000 Continuous Access Journal Software User and Reference Guide, v01 (T5278-96001, June 2007)

Table 14 Relationship between Additional Shared Mem ory and Total Number of
Bitmap Areas in th e Storage System
Additional Shared Memory for Continuous Access Journal To tal Number of Bitmap Areas
in
the Storag e System
No additional shared memory for Continuous Access Journal
0
Additional shared memory for Continuous Access Journal is installed
7,424
Extension 1
16,384
Extension 2 32,768
Extension 3
44,256
Extension 4
65,536
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 14 on page 45 and the required
number of bitmap areas you calculated:
The maximum number of pairs = ( ↓ Numb er 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.
Note: If the calculated maximum number of pairs exceeds 32,768, the actual maximum numb er
of pairs is limited to 32,768.
Note: The capacity of OPEN-V is variable. To get the maximum number of pairs of O PEN-V,
calculate the number by using the formula.
Caution: The bitmap areas that are used for Continuous Access Journal are also used for
Continuous Access. If you use both Continuous Access and Continuous Access Journal, use the
total number of both pairs.
Journal Groups
The Continuous Access Journal journal groups have the following requirements:
• Each Continuous Access Journal pair must be assigned to only one journal group.
•
Table 15 on page 45 shows the specifications for journal groups.
Table 15 Journal Group Specification s
Item
Support Specificatio ns
Number of journal groups
Up to 256 journal groups (No. 0 - 255) per storage system
Note: The recommended number of journal groups is up
to
16.
Number of data volumes in a journal
group
Up to 4,096
Number of journal volumes in a journal
group
Up to 64
Number of Mirror IDs
Up to 4(ID No.: 0to3)
Note: If Continuous Access Synchronous uses No. 0, No. 1
to 3 are available for Continuous Access Journal.
The same number of journal volumes is not required in a master journal group and restore journal
group that are paired.
A Mirror ID is required for a configuration that will be supported in the future within the 3-data center
(3DC). In the future, we might support setting t wo or more restore journal groups for one master journal
group. Each pair relationship in a journal group is called a Mirror. The Mirror ID identifies two or
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