The advantage of zone transfers (
IXFR) is that it's a standardized way for nameservers to synchronize zone data.
It uses the same on-wire format for records that the nameservers need to support for regular responses, so there is no reliance on specific file formats, etc.
The implication of this is two-fold:
- The slave server already knows what is going on (it initiated the transfer) and will not need further interaction to reload data from files.
- There is no requirement that master and slave are the same nameserver implementation or even use the same form of storage for zone data.
That said, if all the servers are running BIND (preferably same or similar version) and no dynamic updates or similar are used (does not seem like a good approach to handle journals in this way), it should cause no issues to have multiple master servers if you ensure the files are properly synchronized and reloaded.