Installation guide

miimon=100 downdelay=300 updelay=300 primary=eth1
Note that bond0 uses balance-alb mode and ARP-based monitoring, whereas bond1 calls for mode 1 (failover)
using mii link status monitoring. These are provided as working syntax examples. You can run both with mi-
imon, if preferred, or other differences in your optionsbut both issues mentioned above are covered. We force
the kernel to load the NIC modules first to address the device "renaming"/"reordering" issues, and the syntax
showed above will allow multiple instances of the bonding driver to be loaded into the kernel so that different
options can be used on each bond device. One will be named bond0, the other will be named bond1.
If you have several network adapters with multiple interfaces, you can eliminate a single point of failure by
bonding interfaces from different network adapters. For example, the above case configures bond0 using eth0
and eth2 while bond1 uses eth1 and eth3.
Note that any time you need to change the bonding configuration on the system, you will need to stop the net-
work ('service network stop'), then remove all instances of the bonding driver ('rmmod bonding', 'rmmod
bond0', etc.). Then restart the network ('service network start') and the new configuration changes should take
effect.
Use the output of 'cat /proc/net/bonding/bond0' (or bond1, etc.) to confirm that the desired bonding configura-
tion options are configured.
Changing Network Adapter Settings
To check the speed and settings of network adapters, use the ethtool command which works now for most
NICs. For example, to check the adapter settings of eth0, run:
# ethtool eth0
To force a speed change to 1000 full duplex, run:
# ethtool -s eth0 speed 1000 duplex full autoneg off
To make a speed change permanent for eth0, set or add the ETHTOOL_OPT environment variable in
/etc/sysconfig/network-scripts/ifcfg-eth0:
ETHTOOL_OPTS="speed 1000 duplex full autoneg off"
This environment variable is sourced in by the network service scripts each time the network is started. Howev-
er, some network interface parameters can not be specified as ETHTOOL_OPTS options. For example, ethtool
options -A and -K are not processed through ETHTOOL_OPTS (see the ethtool manpage for details). These
options can be used to set tx/rx flow control and enable/disable the TCP Segmentation Offload (TSO) feature on
the network card. TSO, also known as "large send", enables the protocol stack to offload portions of outbound
TCP processing to a network interface card, reducing CPU utilization and improving performance.
The corresponding ethtool command can be placed into an "install" statement in /etc/modprobe.conf.
Make sure tx/rx flow control on the network interface corresponds to the settings on the switch.
For example, to disable TSO on e1000 interfaces:
install bond0 /sbin/modprobe bnx2; /sbin/modprobe e1000; \
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