Versant FTS (V/FTS) is an add-on software module for the Versant Database Engine commonly known as a Fault Tolerant Server configuration. V/FTS provides automatic server fail-over and complete error recovery from hardware or software failures. V/FTS is a critical component for all 24/7 application scenarios and SLAs > 99%.

How V/FTS Works

Versant FTS uses a synchronous replication protocol between two database server instances, supporting transparent application to database server re-synchronization in the event of a server side hardware or software failure. The synchronous database replication protocol "mirrors" the contents and operations of one database server with a second instance in a predictable and reliable process, using a distributed two-phase commit protocol.

No significant changes to the application are necessary. Two database servers, a master and a replica (the FTS pair) are kept in sync transactionally, replicating every operation in a distributed two-phase commit protocol. Versant transparently switches the application over to the replica server if a hardware or software failure occurs . Once the original master becomes available again, Versant automatically re-synchronizes the FTS pair and returns to a fully fault tolerant mode.

Benefits

V/FTS provides local as well as geographically remote hardware and software redundancy, protecting a Versant Database installation at a very high degree against the unavailability of data, therefore, V/FTS is highly recommended for mission critical applications.

V/FTS eliminates literally any downtime during a fatal server failure. V/FTS is configuration driven by the application process to support "in-flight" transaction recovery on failure. This approach offers a distinct advantage over the log based replication commonly found in database products.

Alternatively, Versant also offers an Asynchronous Database Replication Tool.

Please contact sales@versant.com for more information on the V/MC add-on module.