Root DNS servers may be the most typical primary(not read-only) DNS servers. There are currently 13 IP addresses for root DNS servers; however, considering the IP anycast technology, more than 13 root DNS servers are deployed worldwide.
If someone wants to update a DNS record for all root DNS servers, is there some sync or replication mechanism between all these DNS servers?
More complex, if two people want to update the same DNS record simultaneously, how does DNS solve the potential conflict?
e.g., person A updated a DNS record r1 to r2 on a.root-servers.net.(deployed at region A), and at the same time, person B updated the same DNS record r1 to r3 on a.root-servers.net.(deployed at region B); moreover assuming there is significant network latency between region A and region B.
The second problem is similar to a database cluster in that there is more than one primary database server, and these primary servers sync data from all other primary servers.
Answer found here, as the question was crossposted to ServerFault :