High Availability Guide : Administering and configuring HotStandby : Performance tuning : Tuning replication performance with safeness and durability levels
  
Tuning replication performance with safeness and durability levels
The performance of data replication during normal operation depends on the setting of the durability level and safeness level. Additionally, when 2-safe replication is used, the acknowledgement policy that is used in 2-safe mode affects the latency time, as perceived by the application. For more information, see Performance and HotStandby.
See also
Performance tuning