The standard way for transmitting zone updates from a Primary Nameserver to a Secondary Namserver is NOTIFY+XFR, with out-of-protocal zone provisioning on the Primary and the Secondary. The rather new catalog zones helped to automate the zone provisioning on the Secondary, but zone updates still use NOTIFY+XFR with additional freshness checks performed by Secondary. This works fine when hosting hundreds or thousands of zones, but creates challenges when hosting millions of zones: NOTIFYs and XFRs may fail, leading to inconsistent Secondarys. And even worse, as the Primary does not know the state on the Secondary, and vice versa, out of protocol monitoring is needed to verify that a Secondary is in sync with the Primary and potentiall fix inconsistencies. A new approach should ensure that all zones updates reliable end up in the Secondary and ease the monitoring.
This talk will highlight the current problem when having Secondaries with millions of zones, and want's to start a discussion for new approaches to keep Secondaries in sync with their Primaries.