SymmetricDS is an asynchronous data replication software package that supports multiple subscribers and bi-directional synchronization. It uses web and database technologies to replicate tables between relational databases, in near real time if desired. The software was designed to scale for a large number of databases, work across low-bandwidth connections, and withstand periods of network outage.
By using database triggers, SymmetricDS guarantees that data changes are captured and atomicity is preserved. Support for database vendors is provided through a Database Dialect layer, with implementations for MySQL, Oracle, SQL Server, PostgreSQL, DB2, Firebird, HSQLDB, H2, and Apache Derby included.
Synchronization can be configured to push data or pull data on a periodic basis. SymmetricDS allows for synchronization between two or more tiers of nodes, as might be needed in the following scenarios:
Deployment options include the following:
SymmetricDS is written in Java and licensed as open source software under the GNU Lesser General Public License (LGPL).
The idea of SymmetricDS was born from a real-world need. Several of the original developers were, several years ago, implementing a commercial Point of Sale (POS) system for a large retailer. The development team came to the conclusion that the software available for trickling back transactions to corporate headquarters (frequently known as the 'central office' or 'general office') did not meet the project needs. The developers started an open-source project, now known as SymmetricDS, to build a generalized, flexible software product that would allow scalable replication across heterogeneous databases for the project and for others with similar needs. Over the years, SymmetricDS has been used very successfully in a variety of domains, including but not limited to retail, medical, and telecommunications, and in installations with just a few nodes to tens of thousands of nodes.