A DNS cluster is a group of nameservers that share records with eachother. This allows you to physically separate nameservers that handle the DNS requests from your web servers.
You can configure DNS clusters in WHM's DNS Cluster interface (Home >> Clusters >> DNS Cluster).
If your nameservers exist in different geographical locations and one fails, DNS clusters allow you to maintain DNS functionality. Visitors can still reach the websites that your server hosts. DNS clusters also allow visitors to reach websites more quickly than they could if only one nameserver processes all of the DNS requests.
Before you set up your DNS cluster, consider which structure will be the most efficient. The way in which you link each server determines the speed at which your DNS requests resolve.
Do not use WHM-to-WHM two-way sync configurations. These configurations may cause DNS errors on your servers.
Your severs function more slowly if multiple steps exist between a web server and a nameserver. To improve the performance of your servers, link your web server directly to the DNS servers, as shown below. This eliminates the steps that each request must perform, and your DNS requests will resolve more quickly.
A direct link between the web server and each of two nameservers is optimal.
In this example,
webserver.example.com sends DNS information directly to
If necessary, place the primary nameserver between the web server and the secondary nameserver. For each intermediate server that you add, data will transfer three times slower than for a direct link.
An intermediate nameserver between the web server and secondary nameserver is acceptable.
To create this configuration, set the web server to sync the primary nameserver. Then, set the primary nameserver to synchronize data to the secondary nameserver.
The least optimal configuration uses multiple steps between the web server and nameservers.
If you configure multiple steps between a web server and nameserver, the servers' performance slows.
In this example, for
web1.example.com to communicate with
ns2.example.com, the information must pass through two intermediary servers. This increases the processor load on the servers, because the nameserver software updates the DNS information on each step. This configuration slows the servers' response time considerably.