Tuesday 23 February 2010

My 10 UNIX Command Line Mistakes

A very good (and tragicomic) article. Sometimes we play down the importance of an enter in the cli.

One of my greatest errors was a typo in a Solaris... crontab -r it's not the same as crontab -e (despite the position of the keys!)

Link here

Testing email posting

I hope this works!

Enviado desde mi iPhone

Tuesday 16 February 2010

Bonding interfaces in Linux

Bonding interfaces provides lb/ft to a network connection. So, if you have a lot of nics and a managed switch (supporting trunking), bonding will be a very good option!

First, create a bond interface file:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0
IPADDR=x.x.x.x
NETWORK=x.x.x.x
NETMASK=x.x.x.x
USERCTL=no
BOOTPROTO=none
ONBOOT=yes

Next, set the first interface in the bond:
# vi /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

Then, the second interface:
# vi /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

Add the bonding module to the modules configuration:
# vi /etc/modprobe.conf
alias bond0 bonding
options bond0 mode=0  miimon=100

Mode 0 for fault tolerance, mode 1 for load balance.

To see a full list of the bonding available modes, go to the official Red Hat KB article here.

Check the bonding module:
# modprobe bonding

Restart the network service:
# service network restart

Check the status of the bond:
# less /proc/net/bonding/bond0

Bonding Mode: load balancing (round-robin)
MII Status: up
MII Polling Interval (ms): 0
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:59

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:63

Thats all... always remember to check /proc/net/bonding/bond0 for link failures.