RHEL 5 Bonding Mode Options setting should be set in the bonding configuration file:
Bonding configuration in modprobe.conf did not work for my customer therefore I made the changes below to get bonding working correctly. Also here is an article relating to the topic: https://bugzilla.redhat.com/show_bug.cgi?id=247718#c1
==> vi /etc/sysconfig/network-scripts/ifcfg-bond0
==> Add the following line:
BONDING_OPTS="mode=1 miimon=100 primary=eth0"
==> Save the file and restart the network.
==> Verify that the mode is correct:
cat /proc/net/bonding/bond0 | grep "Bonding Mode"
Below are different modes available:
mode=0 (balance-rr)
Round-robin policy: Transmit packets in sequential order from the first available slave through the last. This mode provides load balancing and fault tolerance.
mode=1 (active-backup)
Active-backup policy: Only one slave in the bond is active. A different slave becomes active if, and only if, the active slave fails. The bond's MAC address is externally visible on only one port (network adapter) to avoid confusing the switch. This mode provides fault tolerance. The primary option affects the behavior of this mode.
mode=2 (balance-xor)
XOR policy: Transmit based on (source MAC address XOR'd with destination MAC address) modulo slave count. This selects the same slave for each destination MAC address. This mode provides load balancing and fault tolerance.
mode=3 (broadcast)
Broadcast policy: transmits everything on all slave interfaces. This mode provides fault tolerance.
mode=4 (802.3ad)
IEEE 802.3ad Dynamic link aggregation. Creates aggregation groups that share the same speed and duplex settings. Utilizes all slaves in the active aggregator according to the 802.3ad specification.