DHCP failover lease balancing with nearly saturated pools

Jack Kielsmeier jackkiel at netins.net
Thu Jan 29 14:39:46 UTC 2009

I understand. I'm using it in a way it was not intended.

So basically, at least currently, there is not a way to tell one server
to round up and the other to round down when balancing leases.

That's alright. I shouldn't be letting my pools become this saturated
in the first place.

Thank you for the help.
Jack Kielsmeier <jackkiel at netins.net>

> On Wed, Jan 28, 2009 at 04:53:37PM -0600, Jack Kielsmeier wrote:
> > The primary server hands out leases, and the pools on busy subnets are
> > balanced every 5 minutes or so. When there is only one lease left, the
> > secondary won't balance that lease over to the primary.
> This is because there's an odd number of leases remaining.  If each
> server opted to 'round up' from 0 to 1 lease to give away to the
> peer, then in this (and other) cases, they would never stop giving 1
> lease to each other to try and balance the pool every go round.
> Failover isn't really well designed for the case where the servers
> don't see all the broadcast traffic, I don't really have an easy
> answer for that.
> -- 
> David W. Hankins	"If you don't do it right the first time,
> Software Engineer		     you'll just have to do it again."
> Internet Systems Consortium, Inc.		-- Jack T. Hankins

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