Network is frequently going off
 

Hi,

I am installing new IBM X3650 Servers 6 nos at a customer place where all the servers will be loaded with RHEL 6. After loading I have found I am not getting network connection - even ethernet icon is crossed on desktop but I have configured IP (10.10.10.0 / 255.255.255.0), all the systems are connected through a switch which is also working. I am loading RHEL 6.3 (2.6.32-279.el6.x86_64). Moreover I have found the following -

With "service network status" - systems are showing -
'Currently configured devices : lo eth0 eth1 eth2 eth3 usb0' and 'Currently active devices : lo eth0 eth1 eth2 eth3 usb0'

Again when putting "service network restart" giving follwoing message -
Shutting down interface eth0 : Error : Device 'eth0' (/org/freedesktop/NetworkManager/Devices/0) disconnecting failed : This device is not active [FAILED] and all ethernet ports showing the same error only port no is changing but Loopback is properly shutting down and coming up.

I have tried with disabling the firewall and selinux but same problem.

Server configuration is 2 x E5-2620 CPU, 48Gb RAM and 2 x 600GB HDD in RAID 1

please help.

With RHEL6 they started using Network Manager which doesn't play so well with manually configured interfaces (e.g. direct edits of ifcfg-eth<#>).

Also it doesn't like the old style of creating aliases e.g manually creating ifcfg-eth2:1 to make an alias IP on eth2 separate from the main IP of eth0. I found it actually treated that as a new interface and would load it in place of the next eth<#> even if I'd defined that so that the IP shown in ifconfig for eth3 would be the one I assigned in ifcfg-eth2:1 rather than the one I'd assigned in ifcfg-eth3.

Instead it adds aliases to the main ifcfg-eth<#>.

You can bounce Network Manager with "service NetworkManager stop" then "service NetworkManager start".

Here we opted to turn off Network Manager alltogether so we could use the old way of doing it. Do the stop above then run
"chkconfig NetworkManager off".

I originally read about this at RedHat's site:
https://access.redhat.com/site/solutions/32652

It has been a while but I think they actually have fixed this issue in later RHEL6.x releases but I haven't had to muck with aliases on recent installs.