B2B Integration : A Practical Guide to Collaborative E-commerce

52 B2B Integration — A Practical Guide to Collaborative E-commerce
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Figure 3.3. — Primary site data replication
applications in the system have to access data from the master site in
order to do any update operations. Replication captures and stores
changes made to the data at the primary site before forwarding and
applying them to each data source.
Bi-directional data replication
In bi-directional data replication architecture, data replication processes
run on two or more data sources with each replicating data to one
another (see Figure 3.4). One of these data sources may even be a
primary site. In this model, the data that is being replicated from one
site to another can be the same (all sites maintain master copy of the
same data) or different (all sites maintain master copy of different data
segments). Sites that contain a subset of the data are also known as
snapshot sites.