[Pdns-users] Help with mydns backend

Otto Moerbeek otto at drijf.net
Fri Feb 8 08:52:33 UTC 2019

On Thu, Feb 07, 2019 at 05:11:57PM +0000, Rob Campbell wrote:

> Hi,
> I'm trying to switch from mydns-ng to powerdns 4.1.6 with the mydns
> backend. It seems to be working fine on my quietest nameserver but on a
> busy one it starts returning REFUSED to queries after a few minutes and I
> can't work out why as it's not logging any errors. I tried setting
> loglevel=6 and still didn't get anything logged. How can I get some logs
> showing why it's returning REFUSED?
> Seems like we ramp up to over 70 TCP connections quite quickly and we're
> fine at first but once we hit that many either the backend can't keep up or
> we're hitting some limit I've not found.

Try checking the mysql max_connections parameter. That is a parameter
that can be set in the my.cnf config file and runtime as well iirc.
Mysql will normally log an error if the max connection limit is hit.
Where it logs is depedendent on its configuration.


Replace the version with your particular mysql version.

I do not know how many mysql connections the mydns backend is supposed
to use. If increasing the limit does not work out, we can investiate

Migration to the gmysql backend is a good thing, considering the
limited features of the mydns backend.


> Config is:
> launch=
> security-poll-suffix=
> server-id=
> include-dir=/etc/powerdns/pdns.d
> setgid=pdns
> setuid=pdns
> version-string=anonymous
> max-tcp-connections=1024
> receiver-threads=8
> reuseport=yes
> cache-ttl=60
> loglevel=6
> launch+=mydns
> mydns-soa-active=no
> mydns-rr-active=no
> Can anyone help me work out why it's refusing queries?
> Kind regards,
> Rob Campbell.

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