HP P6000 Continuous Access Software - Manual (Page 89)

The default maximum value depends on the controller software version and is expressed as a
multiple of the total capacity of the virtual disks in the DR group. For example, if the DR group
contains virtual disks with a total of 10 GB and the multiple is 1x then the default maximum size
for the log disk is 10 GB.
For specific values, see Controller software features - remote replication .
When creating disk groups, ensure there is sufficient space for log disks to expand to their maximum
size. HP recommends creating DR group log disks in near-line disk groups, if available. Otherwise,
create log disks in the online disk groups with the most free space.
Low-level refresh
Update replication manager database entries by manually performing a discovery and refresh of
individual DR groups. To update the DR group pair, apply a low-level refresh to the source and
destination DR groups.
The action does the following:
•
Performs a discovery refresh at the storage system level to gather the properties of the specified
DR groups, including the log disks.
•
Updates the replication manager database with the new properties.
Managed sets of DR groups
Managed sets of DR groups require careful planning. Consider the following guidelines:
•
Some DR group actions are permitted only on source DR groups; other actions are permitted
only on destination DR groups. See
Using DR group actions .
•
HP recommends that you create separate managed sets for source and destination DR groups.
When you conduct failover operations, you can perform the actions that correspond to the
new roles of the managed set.
•
Source and destination DR groups (from different DR group pairs) can be members of the
same managed set.
•
The source and destination DR group in a DR group pair cannot be members of the same
managed set.
•
If you plan to use DR group managed sets for failover operations, ensure the managed sets
are controlled by the same management server at the time of failover.
Normalization
Normalization is a replication background process which verifies, on a block-by-block basis, that
data is identical on a source virtual disk and its replica. When the source and its replica have
identical data, they are said to be normalized or in a normalized state. The following types of
normalization can apply.
DR group normalization
DR group normalization is a process which verifies that data is identical on source virtual disks
and their remote copies.
Some actions should not be performed during remote copy normalization. When creating jobs,
use wait commands to ensure that normalization is completed. See the WaitDrGroupNormalization
job command.
The disks in a DR group cannot become normalized while any of the following conditions are in
effect:
•
Remote replication is suspended. See suspension state.
•
An intersite link is down.
DR group concepts 89