Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual page 604

Chapter 41. General Parameters and Modules
address for one of the slave NICs. Once this link is established, transmissions are sent out
sequentially beginning with the first available interface.
• broadcast or 3 — Sets a broadcast policy for fault tolerance. All transmissions are sent on all
slave interfaces.
• 802.3ad or 4 — Sets an IEEE 802.3ad dynamic link aggregation policy. Creates aggregation
groups that share the same speed and duplex settings. Transmits and receives on all slaves in
the active aggregator. Requires a switch that is 802.3ad compliant.
• balance-tlb or 5 — Sets a Transmit Load Balancing (TLB) policy for fault tolerance and
load balancing. The outgoing traffic is distributed according to the current load on each slave
interface. Incoming traffic is received by the current slave. If the receiving slave fails, another
slave takes over the MAC address of the failed slave.
• balance-alb or 6 — Sets an Active Load Balancing (ALB) policy for fault tolerance and load
balancing. Includes transmit and receive load balancing for IPV4 traffic. Receive load balancing
is achieved through ARP negotiation.
num_unsol_na=<number>
Specifies the number of unsolicited IPv6 Neighbor Advertisements to be issued after a failover
event. One unsolicited NA is issued immediately after the failover.
The valid range is 0 - 255; the default value is 1. This option affects only the active-backup
mode.
primary=<interface_name>
Specifies the interface name, such as eth0, of the primary device. The primary device is the
first of the bonding interfaces to be used and is not abandoned unless it fails. This setting is
particularly useful when one NIC in the bonding interface is faster and, therefore, able to handle a
bigger load.
This setting is only valid when the bonding interface is in active-backup mode. Refer to /
usr/share/doc/kernel-doc-<kernel-version>/Documentation/networking/
bonding.txt for more information.
primary_reselect=<value>
Specifies the reselection policy for the primary slave. This affects how the primary slave is chosen
to become the active slave when failure of the active slave or recovery of the primary slave occurs.
This option is designed to prevent flip-flopping between the primary slave and other slaves.
Possible values are:
• always or 0 (default) — The primary slave becomes the active slave whenever it comes back
up.
• better or 1 — The primary slave becomes the active slave when it comes back up, if the
speed and duplex of the primary slave is better than the speed and duplex of the current active
slave.
• failure or 2 — The primary slave becomes the active slave only if the current active slave
fails and the primary slave is up.
The primary_reselect setting is ignored in two cases:
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