Boost Reliability with Ethernet Bonding and Linux

“An easy, inexpensive way to double up Ethernet interfaces to
get more more bandwidth and reliability is called Ethernet bonding.
While Gigabit Ethernet is all exciting and the hot new fad, you can
get a lot of mileage out of using Ethernet bonding to give your
existing gear a nice boost without spending much extra money. Just
stuff two ordinary 10/100 Ethernet interfaces into a machine, tweak
a few configuration files, and you’re in business. If one fails you
won’t lose connectivity. It is a good cheap upgrade for your
servers–you’ll have several options for configuring load balancing
and failover, and with the right gear you’ll get an instant
bandwidth boost by combining the bandwidth of the two
interfaces.

“To increase performance by combining the bandwidth of each NIC,
you need a switch that supports link aggregation. Or you can use a
special option in the kernel’s bonding driver. This does some ARP
(address resolution protocol) trickery to combine the bandwidth of
the two NICs. You’ll see a bit of a CPU hit, but it shouldn’t be
much. This must be supported by the interface’s driver; if it isn’t
then your only option is a smart or managed switch that supports
802.3ad…”

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