ASYNC mode

In ASYNC mode, sending logs to standby and writing logs to primary disk are done in parallel. ASYNC mode does not wait for ack messages from the standby, primary system throughput is minimum (log write rate, log send rate). ASYNC mode is applicable for WAN application. Network transmission delay does not impact performance in this mode. However, if the primary database fails, there is a higher chance that logs in transit are lost (not replicated to standby).

Parent topic: Description of the HADR Modes