On Tue, 2012-03-20 at 10:36 -0400, Nikolaus Rath wrote:
> On 03/20/2012 09:55 AM, Myklebust, Trond wrote:
> > On Tue, 2012-03-20 at 09:29 -0400, Nikolaus Rath wrote:
> >> On 03/19/2012 06:25 PM, Rick Macklem wrote:
> >>> Nikolaus Rath wrote:
> >>> ps: Also, although it's not very relevant, getting the MAC address of
> >>> the first ethernet interface isn't easy in FreeBSD. I have no idea
> >>> if the same is true of Linux. (I'd also be worried that "first"
> >>> might not be fixed?)
> >>
> >> It doesn't need to be the same interface all the time, I just meant the
> >> first as in not a specific one.
> >
> > Yes it does have to be the same interface all the time. Otherwise the
> > server cannot tell that this is the same client booting up again.
>
> The likelihood of the interface order changing is certainly much lower
> than the likelihood of the IP address changing (which I understand is
> currently used for the clientid), so the situation would still improve.
It is still easy to find examples of systems for which this breaks:
What do you do for boxes that only have an infiniband connection, for
instance? AFAIK, a lot of IPoIB implmentations don't have reboot-safe
MAC addresses.
Then there is the fact that some of the cheaper NICs don't have
permanent MAC addresses. The MAC address usually gets set as part of the
boot process.
Finally, there is the issue that the NIC is a globally shared hardware
component. If I am running virtual machines in containerised
environments (and yes, I am about to merge the NFS support for
containers into Linux-3.4) then having the NFS clients in all the
different containers identify themselves using the same MAC address will
to lead to some serious brokenness.
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
��.n��������+%������w��{.n�����{��w��� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
