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Date: Tue, 28 Aug 2007 11:44:29 +0200
From: Daniel Hartmeier <daniel@benzedrine.cx>
To: Gergely CZUCZY <phoemix@harmless.hu>
Message-ID: <20070828094429.GF18273@insomnia.benzedrine.cx>
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Cc: freebsd-net@freebsd.org
Subject: Re: carp on multiple interfaces
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On Tue, Aug 28, 2007 at 11:29:31AM +0200, Gergely CZUCZY wrote:

> On a dual-carp scenario on two gateways when both the internal and
> the external IFs are carp(4)'d in a master-slave way and a link
> disconnects only on one side, would this trigger a carp failover
> of the other interface also?

See carp(4)

   net.inet.carp.preempt     Allow virtual hosts to preempt each other.  It
                             is also used to failover carp interfaces as a
                             group.  When the option is enabled and one of
                             the carp enabled physical interfaces goes down,
                             advskew is changed to 240 on all carp inter-
                             faces.  See also the first example.  Disabled
                             by default.

i.e. for your scenario you'd set preempt=1 so all interfaces failover
together, to avoid the problem you describe (which otherwise would
occur, yes).

Daniel