I have a (web) server at a datacenter, which at times (as all datacenters do) has network failures (for like 10-30 minutes).

I have a second server at a different company (datacenter) which I could use as a failover solution.

Now, I was wondering how I could do that? Of course I can mirror the site. The problem is, how do I achieve this: When the main server let's say IP: at datacenter A is not reachable from the outside world, how does my second server at IP: automatically resume its work as main server ?

I don't think that round robin dns would be a solution, because half the requests will be directed to the server which is not reachable.

my servers are windows, IIs


You need to place the load balancer off site. Colocate a redundant hardware loadbalancer in a high-uptime third datacenter(costly but v.nice) or use a cloud service to deploy a redundant software load balancer(way cheaper). If you really can't get the budget, go dns.

| improve this answer | |
  • Are you saying he needs a third server? – johnny Aug 25 '16 at 17:56
  • Well, at least two load balancer units in some form of cluster configuration (operating as one unit) for redundant load distribution/failover. Or a resilient cloud service. – ErikE Aug 25 '16 at 18:09

You are right - round robin DNS would not be a solution in this case. What you need is a DNS service that monitors the availability of your servers and switches over the DNS record for the web site to a failover IP once a problem occurs.

An example of such a service is DNS Made Easy's DNS failover service.

| improve this answer | |
  • thanks for the reply, is there any FASTER solution? the delay with this seems to be 2-4 min ping time + TTL of dns record which means on average 5-8 minutes. Isn't there any way for "instant" switch over? – MirrorMirror Nov 22 '13 at 9:05
  • If you plan to use only the two servers, then no. There are services like CloudFlare (cloudflare.com/overview) that provide cached content when your site goes down. You could also use a proxy server or a load balancer in front of your servers, but that's not very optimal when the servers are in different datacenters, and it adds just one more point of failure. – Ketola Nov 22 '13 at 9:40
  • yeah that's my point, a proxy or a load balancer would still be in one of the datacenters that can fail, so if the datacenter network goes down, so does the loadbalancer/proxy. I will check out this dns mady easy's solution. thank you. – MirrorMirror Nov 22 '13 at 11:35
  • 2
    Also, as a side note, if your hosting provider experiences frequent downtime of 10-30 minutes, I would consider looking for another provider, or even AWS or some other cloud provider. – Ketola Nov 22 '13 at 12:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.