[Samba] Samba with BIND9 DLZ affecting internet speed

[Andrew Bartlett]

On Thu, 2018-12-06 at 22:08 +0200, Zdravko Zdravkov via samba wrote:
> Hi folks.
> 
> I've just experienced strange behaviour with our samba ad configured with
> bind9 dlz and our ftp server (separate machine on the same network).
> 
> In the past few days I've noticed significant drop of the download speed
> from the ftp server.
> As nothing obvious came to my mind I just rebooted our samba AD server.
> Afterwards the speed increased about 9 times, back to what we are used to.
> 
> The ftp server uses the samba AD as dns. That's the only connection between
> the two machines.
> 
> I'm wondering if anyone else can report such troubles or the issue is here
> only.

Each DNS lookup takes the Samba DB lock, no matter what the zone.  This
appears to be the main issue here. 

We need to cache the list of zones we have so we don't need to get the
lock.

In the meantime, set your FTP server to reference a caching BIND9 that
only forwards the Samba zone to the Samba DC.

Andrew Bartlett

-- 
Andrew Bartlett                       http://samba.org/~abartlet/
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba