On Fri, Aug 3, 2012 at 5:43 PM, Konstantin Olchanski <[log in to unmask]> wrote:
> On Fri, Aug 03, 2012 at 04:15:24PM -0400, Nico Kadel-Garcia wrote:
>> On Fri, Aug 3, 2012 at 2:15 PM, Konstantin Olchanski <[log in to unmask]> wrote:
>> > On Thu, Aug 02, 2012 at 06:51:11PM +0000, Adam Bishop wrote:
>> >> Yesterday afternoon the core router on our network decided to have a short nap and stopped routing packets for an hour or so. Layer 2 connectivity was not affected.
>> >>
>> >> As the DHCP server is on a different VLAN to most of my SL servers, a few of them were unable to renew their DHCP leases.
>> >
>> >
>> > If you are using SL6 and the NetworkManager: https://bugzilla.redhat.com/show_bug.cgi?id=829499
>>
>> If you're using NetworkManager for *anything* on a server, don't.
>>
>
>
> This was and still is good advice for SL5 based systems.
>
> On SL6, (after some initial doubts,) I find the NetworkManager to be quite
> good at handling statically configured interfaces (see note 1).
>
> For DHCP-configured addresses, it seems to work well enough, except for the referenced bug,
> which is NOT a regression from SL5 without NM (see note 2).
>
> YMMV, as always.
>
> Note 1: Why use NM to manage static IP addresses?!? It so happens that
> for computers with 2 network interfaces, and NM will assign the one static IP address
> to the interface that has a cable plugged into it. No need to remember which plug
> on the back of the computer is eth0 or eth1 and no need to cover the "wrong" plug
> with black tape. Plus the NM GUI nm-connection-editor is better than the old
> system-config-network GUI and I can still vi the config files directly.

A pair bond configured correctly in failover mode, "mode=1", will
handle this perfectly and will handle simutaneous *live* network
connections, so you get failover. But NetworkManager, and the GUI's
tied to it, don't correctly handle pair bonding or the options
necessary to set it up, at least in my experience up to and including
SL 6.2

> Note 2: SL6 with NM usually survives a network outage, but SL5 without NM does NOT survive
> long network outages because of a ypbind crash (https://bugzilla.redhat.com/show_bug.cgi?id=717069)

ypbind..... is its own fascinating and separate issue. But what in
intriguing little bug!!!