ASA - Optimizing High Availability
In an ASA high-availability arrangement, there are several options to choose from.
In the Active/Standby failover setup, the failover process can take several seconds to complete. This is because it involves several steps such as health checks, stateful information transfer, and role switching, which can take some time.
To potentially reduce failover time, you can adjust the failover poll time using the failover polltime command. However, setting this value too low may cause unnecessary failovers. Additionally, Bidirectional Forwarding Detection (BFD) can improve failover times but is only supported on Firepower 9300 and 4100 models. Adjusting these parameters should be done cautiously to avoid unexpected results. For more detailed configurations, refer to the Cisco documentation on ASA failover.
To achieve zero downtime in the event of a failure, it is preferrable to configure Active/Active failover.
The primary goal of failover is to provide a backup in case the primary system fails, and is not necessarily there to ensure zero downtime. However, using the above guidelines, it is possible to optomize the high availability setup to adhere to your needs.
Links:
https://networklessons.com/switching/802-1q-tunneling-q-q-configuration-example/