HP StorageWorks P2000 HP StorageWorks P2000 G3 MSA System SMU Reference Guide - Page 103

Replication actions, Initial replication: When the first replication is initiated

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Replication actions The following figure illustrates actions that occur during a series of replications from System 1 to System 2. 1 Take initial snapshot and initiate replication. 6 Second snapshot taken on replication destination 2 Initial replication consists of a full data copy. volume. This is the second sync point. 3 Take second snapshot and request replication. This 7 Other snapshots can be taken and replication initiated can be taken while the initial replication is in progress. on the external-view volume while replication is in 4 Snapshot taken on replication destination volume. This is the first replication sync point. progress. These snapshots are queued waiting for prior replications to complete. These replication snapshots will not become sync points until their 5 When the initial replication is complete, the second replications are complete. replication automatically starts. Only the data changed since Snap 1 is replicated. Figure 5 Actions that occur during a series of replications The figure above illustrates initial, delta, and queued replications: • Initial replication: When the first replication is initiated, a snapshot of the external-view volume is taken and every block of data is then copied to the replication destination volume. When the copy is complete, the first snapshot is taken on the replication destination volume, creating the first sync point. This sync point can be used to determine the delta data from that sync point to a later snapshot. Actions 1-4 are the initial replication. • Delta replications: Delta data is the "list" of 64-Kb blocks that differs between the last snapshot replicated and the next snapshot to be replicated. This delta data is then replicated from the replication snapshot on the external-view volume to the replication destination volume. Once the initial replication has completed, all future replications for that replication set will be delta replications so long as sync points are maintained. Action 5 is a delta replication. HP StorageWorks P2000 G3 MSA System SMU Reference Guide 103

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HP StorageWorks P2000 G3 MSA System SMU Reference Guide
103
Replication actions
The following figure illustrates actions that occur during a series of replications from System 1 to System 2.
Figure 5
Actions that occur during a series of replications
The figure above illustrates initial, delta, and queued replications:
•
Initial replication: When the first replication is initiated, a snapshot of the external-view volume is taken
and every block of data is then copied to the replication destination volume. When the copy is
complete, the first snapshot is taken on the replication destination volume, creating the first sync point.
This sync point can be used to determine the delta data from that sync point to a later snapshot. Actions
1–4 are the initial replication.
•
Delta replications: Delta data is the “list” of 64-Kb blocks that differs between the last snapshot
replicated and the next snapshot to be replicated.
This delta data is then replicated from the
replication snapshot on the external-view volume to the replication destination volume. Once the initial
replication has completed, all future replications for that replication set will be delta replications so long
as sync points are maintained. Action 5 is a delta replication.
1
Take initial snapshot and initiate replication.
2
Initial replication consists of a full data copy.
3
Take second snapshot and request replication. This
can be taken while the initial replication is in progress.
4
Snapshot taken on replication destination volume. This
is the first replication sync point.
5
When the initial replication is complete, the second
replication automatically starts. Only the data
changed since Snap 1 is replicated.
6
Second snapshot taken on replication destination
volume. This is the second sync point.
7
Other snapshots can be taken and replication initiated
on the external-view volume while replication is in
progress. These snapshots are queued waiting for
prior replications to complete. These replication
snapshots will not become sync points until their
replications are complete.