Managing HP Serviceguard A.12.00.00 for Linux, June 2014

After the failure of a card, messages are still carried on the bonded LAN and are received on the
other node, but now eth1 has become active in bond0 on node1. This situation is shown in
Figure 24.
Figure 24 Bonded NICs After Failure
Various combinations of Ethernet card types (single or dual-ported) and bond groups are possible,
but it is vitally important to remember that at least two physical cards (or physically separate
on-board LAN interfaces) must be used in any combination of channel bonds to avoid a single
point of failure for heartbeat connections.
3.5.5 Bonding for Load Balancing
It is also possible to configure bonds in load balancing mode, which allows all slaves to transmit
data in parallel, in an active/active arrangement. In this case, high availability is provided by the
fact that the bond still continues to function (with less throughput) if one of the component LANs
should fail. The user should check the Bonding documentation to determine if the hardware
configuration must use Ethernet switches such as the HP Procurve switch, which supports trunking
of switch ports. The bonding driver configuration must specify mode 0 for the bond type.
An example of this type of configuration is shown in Figure 25.
3.5 How the Network Manager Works 63