Comparison of Single-Master and Multi-Master Replication v6.2
There are two models of replication systems supported by xDB Replication Server:
- Single-Master Replication (SMR). Changes (inserts, updates, and deletions) to table rows are allowed to occur in a designated primary database. These changes are replicated to tables in one or more secondary databases. The replicated tables in the secondary databases are not permitted to accept any changes except from its designated primary database. (This is also known as primary-to-secondary replication.)
- Multi-Master Replication (MMR). Two or more databases are designated in which tables with the same table definitions and initial row sets are created. Changes (inserts, updates, and deletions) to table rows are allowed to occur in any database. Changes to table rows in any given database are replicated to their counterpart tables in every other database.
For a single-master replication system, a variety of configurations are supported including:
- Replication between PostgreSQL and Advanced Server databases (between products in either direction)
- Replication in either direction between Oracle and Advanced Server
- Replication in either direction between SQL Server and PostgreSQL
- Replication in either direction between SQL Server and Advanced Server
- Replication in either direction between PostgreSQL and Oracle
For multi-master replication, the participating database servers in a given multi-master replication system must be of the same type:
- PostgreSQL database servers
- PostgreSQL database servers and Advanced Servers operating in PostgreSQL compatible mode
- Advanced Servers operating in PostgreSQL compatible mode
- Advanced Servers operating in Oracle compatible mode
A given database cannot simultaneously participate in both a single-master replication system and a multi-master replication system.