Managing HP Serviceguard A.11.20.10 for Linux, December 2012

the others are available as backups. If one interface fails, another interface in the bonded group
takes over. HP strongly recommends you use channel bonding in each critical IP subnet to achieve
highly available network services.
Host Bus Adapters (HBAs) do not have to be identical. Ethernet LANs must be the same type, but
can be of different bandwidth (for example, 1 Gb and 100 Mb). Serviceguard for Linux supports
the use of bonding of LAN interfaces at the driver level. The Ethernet driver is configured to employ
a group of interfaces.
Once bonding is enabled, each interface can be viewed as a single logical link of multiple physical
ports with only one IP and MAC address. There is no limit to the number of slaves (ports) per bond,
and the number of bonds per system is limited to the number of Linux modules you can load.
You can bond the ports within a multi-ported networking card (cards with up to four ports are
currently available). Alternatively, you can bond ports from different cards. HP recommends that
use different cards.Figure 22 shows an example of four separate interfaces bonded into one
aggregate.
Figure 22 Bonded Network Interfaces
The LANs in the non-bonded configuration have four LAN cards, each associated with a separate
non-aggregated IP address and MAC address, and each with its own LAN name (eth1, eth2,
eth3, or eth4). When these ports are aggregated, all four ports are associated with a single IP
address and MAC address. In this example, the aggregated ports are collectively known as bond0,
and this is the name by which the bond is known during cluster configuration.
Figure 3-18 shows a bonded configuration using redundant hubs with a crossover cable.
3.5 How the Network Manager Works 61