CentOS - NIC Bonding

(Similar to NIC Teaming in MS)

(Explanation of NIC bonding is overtaken from: http://wiki.centos.org/TipsAndTricks/BondingInterfaces)

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.

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.

Broadcast policy: transmits everything on all slave interfaces. This mode provides fault tolerance.

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.

• Pre-requisites:
• Ethtool support in the base drivers for retrieving the speed and duplex of each slave.
• A switch that supports IEEE 802.3ad Dynamic link aggregation. Most switches will require some type of configuration to enable 802.3ad mode.

Adaptive transmit load balancing: channel bonding that does not require any special switch support. The outgoing traffic is distributed according to the current load (computed relative to the speed) on each slave. Incoming traffic is received by the current slave. If the receiving slave fails, another slave takes over the MAC address of the failed receiving slave.

• Prerequisite: Ethtool support in the base drivers for retrieving the speed of each slave.

Adaptive load balancing: includes balance-tlb plus receive load balancing (rlb) for IPV4 traffic, and does not require any special switch support. The receive load balancing is achieved by ARP negotiation. The bonding driver intercepts the ARP Replies sent by the local system on their way out and overwrites the source hardware address with the unique hardware address of one of the slaves in the bond such that different peers use different hardware addresses for the server.

Where: “ /etc/modprobe.d/bonding.conf ”

alias netdev-bond0 bonding

Where: “ /etc/sysconfig/networking/devices/ifcfg-bond0 ”

DEVICE=bond0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes
IPADDR=10.0.12.14                                     #<= Change this
NETMASK=255.255.255.0                                 #<= Change this
NETWORK=10.0.12.0                                     #<= Change this
GATEWAY=10.0.12.1                                     #<= Change this
BONDING_OPTS="miimon=100 mode=1"                      #<= NIC Bonding mode
TYPE=Unknown
IPV6INIT=no

Where: “ /etc/sysconfig/networking/devices/ifcfg-eth0 ”

DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=no
TYPE=Ethernet

Where: “ /etc/sysconfig/networking/devices/ifcfg-eth1 ”

DEVICE=eth1
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=no
TYPE=Ethernet

#/etc/init.d/network start

# ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP qlen 1000
    link/ether 00:0b:cd:cb:a8:97 brd ff:ff:ff:ff:ff:ff
3: eth0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc mq master bond0 state UP qlen 1000
    link/ether 00:0b:cd:cb:a8:97 brd ff:ff:ff:ff:ff:ff
4: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
    link/ether 00:0b:cd:cb:a8:97 brd ff:ff:ff:ff:ff:ff
    inet 10.0.12.14/24 brd 10.0.12.255 scope global bond0
    inet6 fe80::20b:cdff:fecb:a897/64 scope link
       valid_lft forever preferred_lft forever

# cat /proc/net/bonding/bond0

Ethernet Channel Bonding Driver: v3.6.0 (September 26, 2009)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: None
Currently Active Slave: eth1
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 7
Permanent HW addr: 00:0b:cd:cb:a8:97
Slave queue ID: 0

Slave Interface: eth1
MII Status: up
Speed: 100 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: 00:08:c7:39:04:58
Slave queue ID: 0

# ethtool bond0

Settings for bond0:
Supported ports: [ ]
Supported link modes: Not reported
Supported pause frame use: No
Supports auto-negotiation: No
Advertised link modes: Not reported
Advertised pause frame use: No
Advertised auto-negotiation: No
Speed: 100Mb/s
Duplex: Full
Port: Other
PHYAD: 0
Transceiver: internal
Auto-negotiation: off
Link detected: yes

#ethtool -k bond0

Features for bond0:
rx-checksumming: on
tx-checksumming: on
scatter-gather: on
tcp-segmentation-offload: off
udp-fragmentation-offload: off
generic-segmentation-offload: off
generic-receive-offload: on
large-receive-offload: on
rx-vlan-offload: on
tx-vlan-offload: on
ntuple-filters: off
receive-hashing: off

- CentOS 6.5

The best documentation is on the Linux Channel Bonding Project page http://sourceforge.net/projects/bonding/
http://www.howtoforge.com/network_card_bonding_centos
http://wiki.centos.org/TipsAndTricks/BondingInterfaces