HP StorageWorks XP Remote Web Console Software - Manual (Page 21)

XP Continuous Access Journal Remote Copy Operations
This section describes the remote copy operations using XP Continuous Access Journal.
Figure 5 (page 21) illustrates the two types of XP Continuous Access Journal remote copy operations:
initial copy and update copy.
Figure 5 Remote Copy Operations
This section describes the following topics that are related to remote copy operations with XP
Continuous Access Journal.
Initial Copy Operation
Initial copy operations have the following properties and perform the following operations:
•
Initial copy operations synchronize data in the primary data volume and data in the secondary
data volume.
•
Initial copy operations are performed independently from host I/Os.
•
Initial copy operations are performed when you create a data volume pair or when you
resynchronize a suspended pair.
•
The initial copy operation copies the base-journal data that is obtained from the primary data
volume at the primary storage system to the secondary storage system, and then restores the
base-journal to the secondary data volume.
If the journal-obtain operation starts at the primary data volume and goes through the following
steps:
1.
The primary storage system obtains all data in sequence of the primary data volume as the
base-journal data. The base-journal contains a replica of the entire data volume or a replica
of updates to the data volume.
2. The base-journal is copied from the primary storage system to the secondary storage system
after the secondary storage system issues a read-journal command.
3. After a base-journal is copied to the secondary storage system, the base-journal is stored in
a restore journal volume in a restore journal group where the secondary data volume belongs.
4. After that, the data in the restore journal volume is restored to the secondary data volume, so
that the data in the secondary data volume synchronizes with the data in the primary data
volume.
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