nameserver and databases (e.g. mysql)

[Marten Lehmann]

Hi,

since everything is working in realtime nowadays I'm asking myself how I 
can update two or three nameservers at the same time.
AXFR zone transfers are a bad idea, because you never know when the 
other nameserver will have a certain zone synchronized. Also, for a new 
zone to be synchronized, the second and third nameserver need a new zone 
entry in the named.conf and they need to be reloaded with rndc.
Also, treating all nameservers as primary, thus creating zones and do 
the reload on each server is not reliable for a realtime interface, 
because one nameserver might be down and the zone creation couldn't be 
done. Or maybe several creations at the same time would interfere and 
create a broken named.conf (since always the whole file has to be 
re-generated).
My goal is to provide an interface to my customers where they can send 
the zone-data and immediately receive a response and can be sure, that 
the zone is created or updated on all three nameservers within seconds. 
I think the only way to achieve this is having a nameserver that uses a 
database instead of zonefiles and serves all requests directly from it. 
Thus the replication mechanisms of the database can keep track of 
updates being processed on all nameservers (e.g. one instance of mysql 
on each nameserver using mysql-replication).

How could I do this with BIND? Actually, I just need an authoritative 
only nameserver, many of the features that BIND offers wouldn't be used 
in my purpose. I heard of the following three projects:

MyDNS (http://mydns.bboy.net/)
PowerDNS (http://www.powerdns.com/)
Mysql-sdb (http://freshmeat.net/projects/bind-mysql/)

I'm not sure which of the projects is the most sophisticated one and 
provides a similar reliability to BIND with zone files. Have you heard 
of them and can send comments? Do you know other stable projects? Do you 
have other solutions for my problem?

Regards
Marten