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I'm building 2 boxes, each will be Static Content Server (NginX) + Load-Balancer (HAproxy) + DNS Server (NSD).

The TTL on each DNS server for (A) records will be something like 30-60 seconds.

Resolving will be like this:

LB1 (NS1) ==resolves==> xx.xx.xx.01 (LB1)

LB2 (NS2) ==resolves==> xx.xx.xx.02 (LB2)

This way, if for any reason one of these LB is down, then expected downtime would be something like 30-60 seconds (the TTL time), as every working LB will resolve to its own IP, when ONE is down, the other LB's DNS Server will be resolving request to its own.

The 2 LBs aren't in the same location, so it might not be an option to set-up a failover IP (or something similar like heart-beat, keepalived etc.)

I have few questions, and also.. willing to really appreciate any suggestions for a solid highly available system.

  • Is there a way I can configure the DNS query time out to something like 2 seconds in my own DNS server (so any DNS query that we get quickly pass to the other server if no response was sent from first one)?
  • These 2 LBs would be having over 30,000 concurrent connections, is this too much?! suggest some good configs in this case that helps keeping my boxes solid?
  • Is this a good setup? eh.. lol.
  • Finally, as far as you know, since the 2 DNS Server are pointing to 2 different IPs does that effect my website SEO?

-- Thanks

Hasan Alsawadi
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1 Answers1

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Is there a way I can configure the DNS query time out to something like 2 seconds in my own DNS server (so any DNS query that we get quickly pass to the other server if no response was sent from first one)?

If you mean you want clients to contact DNS-2 after a query to DNS-1 fails for N seconds, that's the default behavior in clients.

These 2 LBs would be having over 30,000 concurrent connections, is this too much?! suggest some good configs in this case that helps keeping my boxes solid?

At the DNS level this is no problem. At the nginx level, this should also be no problem if you only serve static content.

Finally, as far as you know, since the 2 DNS Server are pointing to 2 different IPs does that effect my website SEO?

no, SEO operates on domain names, not IPs.

michele
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