Configuring a Highly Available Workflow in Workflow Manager 1.0
Workflow Manager is stateless and it will become highly available if you have multiple computers in the farm. The high availability of Workflow Manager is also impacted by the dependent products. Some of the key dependencies are:
Service Bus. Service Bus requires a farm of three computers to achieve high availability. More details are available at Configure a Highly Available Service Bus.
SQL Server. Workflow Manager is dependent on SQL Server’s availability. Please refer to SQL Server documentation on how to achieve high availability for SQL Server.
Workflow Manager 1.0 MSDN Community Forum