DNS Failover

R

Rob

New member
Hi everyone,

I was just wondering which hosting companies (if any) are using DNS failover. If so which company do you use or do you do it yourself though clustering / load balancing etc.
 
In the past we offered the option of 3 name servers (2 onsite and one in South Africa). Is this the kind of failover you mean? ie... the quickest DNS server to respond handles the query. If the US name servers are down then the SA name server would still respond till we fixed the US ones.
 
If the US name servers are down then the SA name server would still respond till we fixed the US ones.
Click to expand...

Yep thats pretty much what i was talking about, then once the primary server was back online the dns automaticially switched back from backup to primary.
I know DNS Made Easy do this type of thing.
 
A switch back is not needed for DNS. As long as you have name servers set up (primary, secondary, tertiary etc...) and the domain name has specified all of the name servers then when the domain is entered in to the address bar the name servers are queried and the first to respond provides the IP address. If one is off line then it just wont respond and one of the other ns will automatically answer. As long as 1 is online then a response will be given. You do not need to specify which handle which request etc...

However, if you have a tertiary name server in Japan for example and the US ns1/ns2 is down then site visitors in the US might notice a larger delay of a few more seconds as the ns3 could take longer to respond due to latency between the US and JP. But it would respond and provide resolution for the name.
 
I believe Matthew is looking for information on DNS that changes the A record for a domain's zone if the site goes down. Once the original site becomes available then the A record is changed back.
 
We have two servers for DNS, both are RAID 1. Most of our customers run their own DNS servers therefore we do not have the need to load balance any traffic to either DNS servers at the moment.
 
Rob said:
Hi everyone,

I was just wondering which hosting companies (if any) are using DNS failover. If so which company do you use or do you do it yourself though clustering / load balancing etc.
Click to expand...

Good question.

Sure, having it raid 1 or load balance is a great idea. I also suggesting splitting the dns servers up in different location as well.

We're a West Coast Hosting company, therefore, we would want to put a DNS server on the East Coast if not somewhere near.
 
I've heard of companys doing this but I assumed they coded there own system for soem reason. Can anyone point me to a place that has software to buy I'd gladly appreciate it.
 
The dns servers don't have to agree on what the IP for an A record is. So the dns server in europe can direct a user to the europe webserver, and the american dns can take the user to the american website etc.

Just set the A records to be short lived (like 60 seconds). That way if europe goes down people will just see the american website until its fixed.

The issue then is to keep those two webservers, mailservers and maybe database servers synced. If you can do that you have an enterprise load-balanced fail-over system for the price of 2 VPS accounts :)
 
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