[Pdns-users] Using AXFR vs. Mysql Replication

Lorens Kockum lorens-pdns-3987 at tagged.lorens.org
Thu Jun 22 18:02:44 UTC 2006

On Thu, Jun 22, 2006 at 10:26:23AM -0700, Max Clark wrote:
> Hi all,
> We have been using the mysql backend with native master->slave
> replication for some time now. Due to growth, distributed nameservers,
> and the desire to make our DNS infrastructure more stand alone we are
> interested in switching to an AXFR based zone replication to the
> public pdns servers which will be feed by masters running against the
> mysql backend.

I would not recommend AXFRs, especially as you have replication

I have two problems with using AXFRs:

    The pdns server does not remember AXFRs or SOA checks so
    that it can re-NOTIFY the slaves who have not AXFRd a given
    zone within some reasonable time. This means that if for
    some reason an UDP NOTIFY packet is lost, the zone wil not
    be updated, and if the NOTIFY is the initial one, the zone
    will not be configured on the slaves until the zone is
    changed and a new NOTIFY is sent.

    When a zone is removed from the master, the slave does not
    recognize that. I would like the slave to remove the zone
    from the database when it expires.

> With mysql native replication zero configuration is required on the
> slave instances to configure new zones - I understand there is a
> configuration option for a supermaster in pdns so that the slaves will
> autogenerate zones based on the master but I am unclear on the proper
> use for deployment.

The slaves need to have the master's IP(s) configured in pdns.conf as
their supermasters. The zones in the master database should not be type
NATIVE any more, but type MASTER. I think that's about it, apart from
the different allow-axfr access lists.


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