Administrator Guide

Figure 1. Process for initial replication
A
User view 1 Step 1: User initiates replication for the first time.
B Internal view 2 Step 2: Current primary volume contents replace S1 contents.
a Primary system 3 Step 3: S1 contents are fully replicated over the peer connection to counterpart
S1, replacing S1 contents.
b Secondary system 4 Step 4: S1 contents replace the secondary volume contents.
c Peer connection
d Primary volume
e Secondary volume
The two internal snapshots for each volume on the primary and secondary systems all have distinct roles. For both systems,
they are labeled S1 (Snapshot 1) and S2 (Snapshot 2) in the two figures above and below. When a replication set is created,
the primary volume and its internal snapshots all contain the same data. The secondary volume and its internal snapshots do not
contain any data. Between the time that the replication set was created and the initial replication occurs, it is possible that hosts
have written additional data to the primary volume.
During initial replication, the following sequence takes place. The user initiates replication on the primary system (step 1). The
current primary volume contents, which might be different than when the replication set was created, replace the contents of
S1 on the primary system (step 2). The S1 data, which matches that of the primary volume, is replicated in its entirety to its S1
counterpart on the secondary system and replaces the data that the secondary system S1 contains (step 3). The S1 contents
on the secondary system replace the contents of the secondary volume (step 4). The contents of the primary and secondary
volumes are now synchronized.
Subsequent replications
The following figure illustrates the internal process that take place in replications subsequent to the initial replication of a single
volume.
Working in the Replications topic
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