Customer asked what it would be worth to give him near 100% reliability. The only way I could think of is to have atleast 2 seperate servers that have atleast 99.xx% reliability. Then if the main went down, the second backup server could take over.
I am trying to see how to implement it though - and I am not sure if this is feasible.
If I had two servers, and each server has it's own name servers - could I work it so that:
1) Primary server
ns1.domain.com & ns2.domain.com
2) Backup server
ns3.domain.com & ns4.domain.com
So if the primary name servers didn't respond, would people's browsers then be compelled to try ns3 and ns4 (and the backup server accordingly)?
Would be a nice value added service. Any thoughts or ideas? Anyone have a nice redundancy plan setup?
I'm fairly sure it doesn't automatically go to like primary nameserver, but rather whichever responds first, and once they are on the site they stay using the name servers. So for example like if someone went to yourdomain.com, and the NS1 name server responded first, however then it went down as they were browsing the site, they would still see a 404.
Isn't that what what two DNS entries are for? Am I not understanding something?
ns2.somehost.com 678.910.11.12 <-- some server somewhere else.
If the primary Nameserver can't be contacted, your next Nameserver will be contacted. Well, I guess that doesn't solve the problem for customers who have already resoved to your primary Nameserver. Did I just answer my own question?
given that the network has 100% uptime, you could monitor the main server and if it goes down, update the routing tables to have the traffic routed to the second box. thats not a biggie, but what are you gonna do with databases? ie, how do you ensure that the db on the second box is up to date? db replication can be tricky, depending on the concurrency and other factors, dr dobbs had an insightful article on that in their august or so issue i think.