Re: Unicast CARP and static arp entries

2012-07-25 Thread Marco Pfatschbacher 
On Wed, Jul 25, 2012 at 12:07:25PM +0200, Henning Brauer wrote:
> * Lee Verberne  [2012-07-19 23:46]:
> > A power supply failed in my 2-node OpenBSD 5.1 unicast CARP cluster
> > recently.  After the failure I noticed that the carp demote counter was
> > being increased by output errors:
> > 
> > carp: carp0 demoted group carp by 1 to 1 (> snderrors)
> > 
> > I tracked this back to the surviving node being unable to arp for the
> > ethernet address of its carppeer.  At least, adding static permanent arp
> > entries stopped the Oerrs on carp0.
> > 
> > I'm planning on adding static arp entries as a best-practice now any
> > time I use unicast CARP.  I didn't see any documentation or list traffic
> > on this topic, though, so I thought I'd ask what others do.  Am I
> > missing something or is this ill-advised?
> 
> hmm, interesting one.
 
I guess the best thing we could do, is to ignore send errors
if unicast carp is being used.
I don't think we can distinguish the ip_output errors to
only ignore failures on missing arp entries.

> not too ill-advised (the common problem with static arp entries
> remain, foremost, they are static, thus changes require extra steps).
> 
> -- 
> Henning Brauer, h...@bsws.de, henn...@openbsd.org
> BS Web Services, http://bsws.de, Full-Service ISP
> Secure Hosting, Mail and DNS Services. Dedicated Servers, Root to Fully 
> Managed
> Henning Brauer Consulting, http://henningbrauer.com/

Re: Unicast CARP and static arp entries

2012-07-25 Thread Henning Brauer 
* Lee Verberne  [2012-07-19 23:46]:
> A power supply failed in my 2-node OpenBSD 5.1 unicast CARP cluster
> recently.  After the failure I noticed that the carp demote counter was
> being increased by output errors:
> 
> carp: carp0 demoted group carp by 1 to 1 (> snderrors)
> 
> I tracked this back to the surviving node being unable to arp for the
> ethernet address of its carppeer.  At least, adding static permanent arp
> entries stopped the Oerrs on carp0.
> 
> I'm planning on adding static arp entries as a best-practice now any
> time I use unicast CARP.  I didn't see any documentation or list traffic
> on this topic, though, so I thought I'd ask what others do.  Am I
> missing something or is this ill-advised?

hmm, interesting one.

not too ill-advised (the common problem with static arp entries
remain, foremost, they are static, thus changes require extra steps).

-- 
Henning Brauer, h...@bsws.de, henn...@openbsd.org
BS Web Services, http://bsws.de, Full-Service ISP
Secure Hosting, Mail and DNS Services. Dedicated Servers, Root to Fully Managed
Henning Brauer Consulting, http://henningbrauer.com/

Unicast CARP and static arp entries

2012-07-19 Thread Lee Verberne 
A power supply failed in my 2-node OpenBSD 5.1 unicast CARP cluster
recently.  After the failure I noticed that the carp demote counter was
being increased by output errors:

carp: carp0 demoted group carp by 1 to 1 (> snderrors)

I tracked this back to the surviving node being unable to arp for the
ethernet address of its carppeer.  At least, adding static permanent arp
entries stopped the Oerrs on carp0.

I'm planning on adding static arp entries as a best-practice now any
time I use unicast CARP.  I didn't see any documentation or list traffic
on this topic, though, so I thought I'd ask what others do.  Am I
missing something or is this ill-advised?

Thanks,
-lee