So for a secondary dns server each slave record has to be setup manually?
or is there a way for it to autocreate the slave record when master is created?
No. I guess it should be possible to use e.g. the remoting framework to add a slave record on the secondary server when a primary record is added on the master by adding the code for a remoting call in the file /home/admispconfig/ispconfig/lib/classes/ispconfig_isp_dns.lib.php
e.g add on line 440:
if($aufruf == 'soa' && is_file('/home/admispconfig/ispconfig/lib/slavedns.php')) include('/home/admispconfig/ispconfig/lib/slavedns.php');
Then create a new file /home/admispconfig/ispconfig/lib/slavedns.php
and inside the file add the code for the remoting call. You will find all information about the dns record (e.g. domain name etc.) in the variable $soa. The $soa variable contains the record from the database table dns_isp_dns, so that the domain name can be accessed with $soa['dns_soa']