HOWTO synchronize a new mirror with old configuration

Hello,

I installed a while ago 2 dns server (ns2 is mirror of ns3). I noticed at that time that ns2 didn't synchronize data that was created BEFORE it was set up as a mirror. At that time I deleted all DNS data and created my domains to get it working with the 2 server having 100% DNS data.

Now I just created the third one (ns1) and I do not want to use the same "turn around".

Can you tell me if there is any official and clean way to do that ?
Partial dump dbispconfig ? or any other tool ??

Thank you in advance.

 

It worked in 5 minutes, thank you very much till