DNS Only Replication to 4 name servers takes extraordinary long holding up the WHM User Interface, > 75 seconds

eugenevdm.host

Well-Known Member
Oct 21, 2019
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Cape Town
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DataCenter Provider
We have a few primary WHM/cPanel servers that are integrated with four independent WHM DNS Only Servers spread on three continents.

When we do anything in the DNS it takes extraordinary long, around 75 seconds for any change, e.g. an addition, an update, a deletion.

The infrastructure and all servers are 100% performant, so I'm quite sure the problem is that the source server communicates with the name server hierarchy and holds up the WHM User Interface until the DNS changes are completed.

I made some DNS changes to a competitor's WHM and their UI immediately came back so I'm almost certain that WHM has a background queue that for some odd reason isn't activated on our servers. Any tips?
 

cPRex

Jurassic Moderator
Staff member
Oct 19, 2014
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Root Administrator
Hey there! This could depend on many different things - the speed of the network between the machines, the speed of each DNS cluster, how many zone files it's trying to load - I'm not sure there is a good answer to this question.

One way you may be able to get more details is if you go to WHM >> Tweak Settings, and then under the "Logging" tab enable the "Enable verbose logging of DNS zone syncing" that will write data to /usr/local/cpanel/logs/dnsadmin_log and could show you which step the slowness is happening. For example, if you tailed that log while making a DNS change, it could show if one specific cluster member takes a long time to sync.