how to combine multiple nics

[Maaz]

OS: SUSE Linux 10 SP1

is it possible to combine 2 nics ?
if one nic goes down due to hardware error(malfunction) the other nic will continue to work, so that services remains available to the client, and machine remains available on the network.

Regards
Maa

[Ivan Ferreira]

Linux provides ethernet bonding. The bonding kernel module allows the configuration of redundant NICs.

[Svetoslav Gyurov · Accepted solution]

Hi,

Yes it is possible by using the linux ethernet bonding driver:

1. configure the bond interface
vi /etc/sysconfig/network/ifcfg-bond0
BOOTPROTO="static"
BROADCAST="10.0.0.255"
IPADDR="10.0.0.10"
NETMASK="255.255.255.0"
NETWORK=""
REMOTE_IPADDR=""
STARTMODE="onboot"
BONDING_MASTER="yes"
BONDING_MODULE_OPTS="mode=balance-alb miimon=100"
BONDING_SLAVE0="eth0"
BONDING_SLAVE1="eth1"


2. make alias and set options for bonding options
# load and configure module
alias bond0 bonding
options bond0 mode=balance-alb miimon=100
alias bond1 bonding
options bond1 mode=balance-alb miimon=100


3. remove old records
vi ifcfg-id-xx:xx:xx:xx:xx:xx
BOOTPROTO='none'
STARTMODE='off'


4. test
modprobe bonding
service network restart
cat /proc/net/bonding/bond0


Typical bonding configuration should look like this:
sve@angmar:~/project/mvn$ cat bond0
Ethernet Channel Bonding Driver: v3.0.1 (January 9, 2006)

Bonding Mode: adaptive load balancing
Primary Slave: None
Currently Active Slave: eth0
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:19:bb:30:21:d0

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:19:bb:30:21:cf

For more information refer to the kernel documentaion:
/usr/src/linux/Documentation/networking/bonding.txt

Good luck!

--
sve

[Maaz]

Thanks Ivan Ferreira, and Svetoslav Gyurov

does "mode=balance-alb" provides High Availability and/or fault tolerance ?

Svetoslav Gyurov, in SUSE options are provided in single quotes in the nic configuration file.

there is no need to configure in /etc/modprobe.conf
I also tried to configure the bonding using YaST, and using mouse clicks its done(nice tool). Yast also doesnt modify the /etc/modprobe.conf.

[Svetoslav Gyurov]

Maaz,

Yes it provides failover in case of a failure of one of the nics. I used this feature to provide HA to the network interfaces in regard to Oracle RAC. I used to have two servers each with four nics connected to two (stacked) switches. So I had two bonded interfaces, one for the public and one for the private network and I never used to have problems with this setup.

Regards,
sve

[Maaz]

Thanks once again Dear Svetoslav Gyurov