Keep DNS available with the right failover setup.
BuckDNS distinguishes changing a DNS resolution path from keeping another DNS server available.
DNS path failover
Configured backup paths can use alternate upstream providers or direct recursion as appropriate. Health checks confirm an outage and verify a backup before switching paths.
BuckDNS continues checking the preferred path and returns after the required successful recovery checks. A backup provider is a resolution-path option, not a second BuckDNS server.
Paired-server availability
Run paired BuckDNS servers with synchronized settings. Configure your network or clients with both server DNS addresses so another server can answer if one becomes unavailable.
Each server serves DNS independently using its accepted configuration. Client resolver behavior influences which server receives requests; simply creating a replica does not redirect all clients automatically.
Configuration sync has limits
Settings synchronization is distinct from automatic promotion to a writable primary. Plan how configuration changes are managed rather than assuming server availability implies promotion.
Each server maintains its own cache. Keep the DNS service reachable on both servers and verify the client configuration as part of deployment.