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Barracuda Load Balancer

Multiport Configuration in a High Availability Environment

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This article refers to firmware 4.2 and higher running on the Barracuda Load Balancer model 640 that includes PORT1 through PORT10.

High availability (HA) is an advanced feature and may not be appropriate for all environments; contact Barracuda Networks Technical Support before enabling this feature.

If you are using HA to cluster two Barracuda Load Balancers:

  • Ensure that the WAN IP Address and VLAN Interface are configured the same on both systems when the WAN IP is on the VLAN Interface.
  • Ensure that the WAN IP Address is configured with the same bond interface.
  • Ensure that the WAN IP Address is on the same VLAN as the bonded interface.

In HA, any link bonding configuration synchronizes to the peer system. Note that when creating an interface bond, selecting the mode 802.3ad (or LACP) does not increase the bandwidth for a single conversation and achieves high utilization only when carrying multiple simultaneous conversations as it attempts to use the same ports for the same conversation.


In Failover, the bonds are created on the peer system, and heartbeat and configuration synchronization continue on the WAN port as usual. The system can monitor one or more of the "un-bonded" ports or the bonds for the Failover on Link Down setting.

The system lists all ports as there is no bond on the system. For example, if there was a bond between PORT2 and PORT3 then you will see PORT1, BOND1, PORT4 and so on.

The bonding information, including the modes (round-robin, active-backup, or 802.3ad/LACP) is synced across the nodes; however, the administrator must ensure proper cabling for it to take effect on a Failover. For example, if PORT2 and PORT3 form a bond on the primary device then the system attempts to use these same ports (PORT2 and PORT3) for the bond on a Failover, therefore the administrator must verify they are connected to the same switch as the bond on the primary.

On the ADVANCED > High Availability page, you can monitor the network ports by selecting them from the Failover on Link Down values. When Enable Network Port Configuration is set to No, you can connect any of the ports to the LAN. This allows traffic to work properly by connecting any ports from device A to device B to the LAN switch. However, to monitor these ports as part of the High Availability Failover mechanism, select the same physical port on device A and device B.

If the WAN IP Address on the Barracuda Load Balancers in a cluster is configured with the same bond interface, and the minimum link falls below the specified Failover value, Failover is still successful. However, the status of the peer on the ADVANCED > High Availability page displays as peer down.

For example, if the systems in HA for a bond using WAN, PORT1-2, and PORT1-4, the minimum link value is 3. In this instance, if PORT1-2 goes down on the Primary System, the Failover is successful, but the Status of both devices displays as down in the ADVANCED > High Availability page.



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