Specifications

Chapter 4: Creating a High Availability Environment 39
Chapter 4
Creating a High Availability Environment
This chapter describes how to create a high availability environment by clustering two Barracuda
Link Balancers. It includes the following topics:
Overview ............................................................................................ 39
Planning Your High Availability Deployment.................................... 42
Creating a Cluster ............................................................................. 44
Removing a System from a Cluster.................................................... 46
Updating Firmware on Clustered Systems ........................................46
Overview
The High Availability option allows you to link two Barracuda Link Balancers as a clustered active-
passive pair. Both systems are connected to the WAN links, but only one is actively processing traffic
at any time. The two systems continuously share almost all configuration settings and monitor each
other’s health.
If clustering two Barracuda Link Balancers is not a viable option, as an alternative, consider
configuring Ethernet Passthrough. This feature is only available on certain models.
Ethernet Passthrough
If Ethernet Passthrough is configured and if the Barracuda Link Balancer fails, all traffic from WAN1
will be passed directly to the LAN. Do not enable this feature in these cases:
• If your network is relying on the Barracuda Link Balancer firewall to perform IP or port address
translation for internal IP addresses.
• If you have clustered systems, because the passive system will take over if this system fails.
Configure the Ethernet Passthrough option by using the
Advanced > High Availability page.
Operation of High Availability (HA)
The active system in a clustered pair handles all of the traffic until one of the following components
experiences a failure or an outage:
• Its connection to the LAN.
• All of its WAN links (administrator configurable option).
• The Barracuda Link Balancer itself.
When one of these conditions is detected, the passive system becomes active and link balances the
traffic from the WAN links.