Linux Bond mode 参数说明
linux系统下bond mode参数说明：（mode=4 在交换机支持LACP时推荐使用，其能提供更好的性能和稳定性）
0－轮询模式，所绑定的网卡会针对访问以轮询算法进行平分。
1－高可用模式，运行时只使用一个网卡，其余网卡作为备份，在负载不超过单块网卡带宽或压力时建议使用。
2－基于HASH算法的负载均衡模式，网卡的分流按照xmit_hash_policy的TCP协议层设置来进行HASH计算分流，使各种不同处理来源的访问都尽量在同一个网卡上进行处理。
3－广播模式，所有被绑定的网卡都将得到相同的数据，一般用于十分特殊的网络需求，如需要对两个互相没有连接的交换机发送相同的数据。
4－802.3ab负载均衡模式，要求交换机也支持802.3ab模式，理论上服务器及交换机都支持此模式时，网卡带宽最高可以翻倍(如从1Gbps翻到2Gbps)
5－适配器输出负载均衡模式，输出的数据会通过所有被绑定的网卡输出，接收数据时则只选定其中一块网卡。如果正在用于接收数据的网卡发生故障，则由其他网卡接管，要求所用的网卡及网卡驱动可通过ethtool命令得到speed信息。
6－适配器输入/输出负载均衡模式，在”模式5″的基础上，在接收数据的同时实现负载均衡，除要求ethtool命令可得到speed信息外，还要求支持对网卡MAC地址的动态修改功能。
以下是摘抄自RedHat官方的详细解释 (原文链接 http://www.linux-kvm.org/page/HOWTO_BONDING)
Modes
It's possible to assign the mode number or the mode name when selecting the mode in the kernel module option.
0 or 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. (This is the default mode if no mode specified)
1 or 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.
In bonding version 2.6.2 or later, when a failover
occurs in active-backup mode, bonding will issue one
or more gratuitous ARPs on the newly active slave.
One gratutious ARP is issued for the bonding master
interface and each VLAN interfaces configured above
it, provided that the interface has at least one IP
address configured. Gratuitous ARPs issued for VLAN
interfaces are tagged with the appropriate VLAN id.
This mode provides fault tolerance. The primary
option, documented below, affects the behavior of this
mode.
2 or balance-xor
XOR policy: Transmit based on the selected transmit
hash policy. The default policy is a simple [(source
MAC address XOR'd with destination MAC address) modulo
slave count]. Alternate transmit policies may be
selected via the xmit_hash_policy option, described
below.
This mode provides load balancing and fault tolerance.
3 or broadcast
Broadcast policy: transmits everything on all slave
interfaces. This mode provides fault tolerance.
4 or 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.
Slave selection for outgoing traffic is done according
to the transmit hash policy, which may be changed from
the default simple XOR policy via the xmit_hash_policy
option, documented below. Note that not all transmit
policies may be 802.3ad compliant, particularly in
regards to the packet mis-ordering requirements of
section 43.2.4 of the 802.3ad standard. Differing
peer implementations will have varying tolerances for
noncompliance.
Prerequisites:
1. Ethtool support in the base drivers for retrieving
the speed and duplex of each slave.
2. A switch that supports IEEE 802.3ad Dynamic link
aggregation.
Most switches will require some type of configuration
to enable 802.3ad mode.
5 or balance-tlb
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.
6 or balance-alb
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.
Receive traffic from connections created by the server
is also balanced. When the local system sends an ARP
Request the bonding driver copies and saves the peer's
IP information from the ARP packet. When the ARP
Reply arrives from the peer, its hardware address is
retrieved and the bonding driver initiates an ARP
reply to this peer assigning it to one of the slaves
in the bond. A problematic outcome of using ARP
negotiation for balancing is that each time that an
ARP request is broadcast it uses the hardware address
of the bond. Hence, peers learn the hardware address
of the bond and the balancing of receive traffic
collapses to the current slave. This is handled by
sending updates (ARP Replies) to all the peers with
their individually assigned hardware address such that
the traffic is redistributed. Receive traffic is also
redistributed when a new slave is added to the bond
and when an inactive slave is re-activated. The
receive load is distributed sequentially (round robin)
among the group of highest speed slaves in the bond.
When a link is reconnected or a new slave joins the
bond the receive traffic is redistributed among all
active slaves in the bond by initiating ARP Replies
with the selected mac address to each of the
clients. The updelay parameter (detailed below) must
be set to a value equal or greater than the switch's
forwarding delay so that the ARP Replies sent to the
peers will not be blocked by the switch.
Prerequisites:
1. Ethtool support in the base drivers for retrieving
the speed of each slave.
2. Base driver support for setting the hardware
address of a device while it is open. This is
required so that there will always be one slave in the
team using the bond hardware address (the
curr_active_slave) while having a unique hardware
address for each slave in the bond. If the
curr_active_slave fails its hardware address is
swapped with the new curr_active_slave that was