Journal group specifications – HP XP Continuous Access Software User Manual
Page 49
Table 16 Journal Group Specifications
Support Specifications
Item
Up to 256 journal groups (Number 0 to 255) per storage
system
The recommended number of journal groups is up to 16.
Number of journal groups
Up to 8,192
In the 3DC configuration which consists of three Continuous
Access Journal sites, up to 16,384.
(8,192 (maximum number of volumes in a mirror)
2 (mirrors)
= 16,384)
Note that whether the maximum number of data volumes
available for a journal group on the local storage system
depends on the number of data volumes that can be registered
to a journal group of the paired storage system.
Number of data volumes in a journal
group
Up to 64
Number of journal volumes in a journal
group
At least 6GB.
If the capacity is below 6GB, the system performance is
unassured because the following problems may occur:
•
The new data cannot be stored because the journal volume
is full, then the host performance goes down.
•
The performance of the initial copy goes down because the
journal volume is full.
•
The journal group is suspended because the journal volume
is full.
•
The indication of usages is invalid.
Capacity of journal volumes in journal
group
Up to 4 (ID Number 0 to 3)
If XP Continuous Access Synchronous uses Number 0, Number
1 to 3 are still available for XP Continuous Access Journal.
However, if the XP Continuous Access Synchronous pair for
delta resync operation is used, No. 1 to 3 are available.
Number of Mirror IDs
The same number of journal volumes is not required in a master journal group and restore journal
group that are paired.
Each pair relationship in a journal group is called Mirror. A Mirror ID is required for a configuration
that will be supported in the future within the 3-data center (3DC). The Mirror ID identifies two or
more mirrors in one journal group. The same Mirror ID is applied to the pair of data volumes.
See
“ 3DC Multi-target Configuration of Three XP Continuous Access Journal Sites” (page 60)
,
“3DC Cascading Configuration of Three XP Continuous Access Journal Sites” (page 65)
, or
Continuous Access Synchronous (3DC Cascading Configuration)” (page 82)
.
See
“XP Continuous Access Synchronous (3DC Cascading Configuration)” (page 82)
for 3DC
configurations.
shows specifications for the relationship between the data volumes, between
the journal volumes, and between the data volume and journal volume in the journal group.
Requirements and Restrictions
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