Forum Discussion
SQL Always On when QUORUM fails
Hello friends,
i have a sql cluster with always on and today i noticed a scenario.
When I restarted the domain / dns server that is my quorum when trying to authenticate to the databases I had difficulty and generated several failures in the cluster of quorum unavailable.
So I asked myself regarding the importance of the availability of my domain controller server to access the databases.
However I have another domain controller server (secondary) which is also DNS.
Can anyone tell me how long it takes servers that authenticate to the domain/dns server need to direct connections to the secondary server?
Can this be adjusted to be faster?
Thanks.
1 Reply
According to below process, it takes 3 seconds for query to secondary DNS server.
The DNS Client service queries the DNS servers in the following order:
1. The DNS Client service sends the name query to the first DNS server on the preferred adapter’s list of DNS servers and waits one second for a response.
2. If the DNS Client service does not receive a response from the first DNS server within one second, it sends the name query to the first DNS servers on all adapters that are still under consideration and waits two seconds for a response.
3. If the DNS Client service does not receive a response from any DNS server within two seconds, the DNS Client service sends the query to all DNS servers on all adapters that are still under consideration and waits another two seconds for a response.
4. If the DNS Client service still does not receive a response from any DNS server, it sends the name query to all DNS servers on all adapters that are still under consideration and waits four seconds for a response.
5. If it the DNS Client service does not receive a response from any DNS server, the DNS client sends the query to all DNS servers on all adapters that are still under consideration and waits eight seconds for a response.
