[Samba] Samba internal dns stops work on load

[José Neto]

Hi!

I'm having some trouble with samba internal dns - it is acting as a
forwarder too.

If a few users (1 or 2) are logged in, OK. But if more users are
logged in, no name is resolved.
So every (exactly) 10 minutes I see high IO usage (samba process
writes about +500MB in disk, I don't know where) and samba logs:

../source4/dsdb/dns/dns_update.c:294(dnsupdate_nameupdate_done)
../source4/dsdb/dns/dns_update.c:294: Failed DNS update - NT_STATUS_IO_TIMEOUT

Samba version: 4.0.11

Global section in smb.conf:

[global]
        workgroup = MYDOMAIN
        realm = mydomain.local
        netbios name = SAMBA01
        server role = active directory domain controller
        log level = 0
        log file = /usr/local/samba/var/smb.log.%m
        os level = 50
        allow dns updates = nonsecure and secure
        dns forwarder = 208.67.220.220

OBS.: I provisioned the domain and used for a time samba version
4.2.0pre1-GIT-6ac6bf9

Thanks in advance!