High Availability Overview,


The below diagram represents a typical high availability architecture. The firewalls and file servers are redundant, and the application servers are load balanced so that as long as one member is still functioning, the cluster will function without interruption.


This setup works by having virtual IP addresses shared between members. So for the 2 firewall machines, there 2 virtual IPs. One for the external interface, and one for the internal interface. This floating IP is what internal clients assign as their default gateway so in case of a failover, the floating IP will be picked up by the active server, same goes for the fileservers.

The technologies used in this diagram are: