[ale] eth numbering change

[Alex Carver]

If you wanted to experiment you could start moving the boards around in
the slots.  Take the board that comes up as eth1 currently and move it
to the other side of the eth0 board (leaving the eth0 board in its
current slot).  If they swap device names then it's just the bus order.

On 2017-02-08 14:02, Brian Stanaland wrote:
> There were no udev rules in place. We set that up so the NICs were named the way 
> they wanted. It's possible that the motherboards were from different production 
> runs. The wired order of the slots isn't something we would specify.
> 
> That answers the question for me.
> 
> Thanks,
> Brian
> 
> 
> On Wed, Feb 8, 2017 at 4:31 PM, Alex Carver <agcarver+ale at acarver.net 
> <mailto:agcarver+ale at acarver.net>> wrote:
> 
>     Others have mentioned persistent information on the system (udev rules,
>     previously seen NICs) but there's also just the basic order of bus
>     enumeration.  Slot 2 might actually be scanned before Slot 1 (bus order
>     is determined by the physical wiring on the board and how they are wired
>     to the bus controller).  If Slot 2 comes up first then the kernel sees
>     whatever is there first and assigns eth0 as the first available device.
>     Then it scans Slot 1 and assigns the next available eth1.
> 
>     On 2017-02-08 11:05, Brian Stanaland wrote:
>      > Hello,
>      >
>      > This one has bugged me for a while.
>      >
>      > I understand that the numbering of network interfaces can change when
>     adding a
>      > network card. What I can't figure out is why it's inconsistent. I have two
>      > identical servers, same mobo, same NICs in slot 1, same firmware, etc. I
>     add a
>      > NIC in slot 2 on both severs and reboot. Why does one show the new NIC as
>     eth0
>      > and the other shows the new NIC as eth1?
>      >
>      > Google only turns up how to set persistence.
>      >
>      > --Brian