Requirements and Prerequisites for High Availability

The two units in a High Availability Failover configuration must:

• Be on a separate chassis; intra-chassis High Availability for the Firepower 9300 is not supported.

• Be the same model.

• Have the same interfaces assigned to the High Availability logical devices.

• Have the same number and types of interfaces. All interfaces must be preconfigured in FXOS identically before you enable High Availability.

High Availability is only supported between same-type modules on the Firepower 9300; but the two chassis can include mixed modules. For example, each chassis has an SM-56, SM-48, and SM-40. You can create High Availability pairs between the SM-56 modules, between the SM-48 modules, and between the SM-40 modules.

For container instances, each unit must use the same resource profile attributes.

For container instances: Do not use cascading instances (using a shared interface) with High Availability. After a failover occurs and the standby unit rejoins, MAC addresses can overlap temporarily and cause an outage. You should instead use unique interfaces for the gateway instance and inside instance using an external switch to pass traffic between the instances.

For other High Availability system requirements, see High Availability System Requirements.