We're in the planning phase to make our web application services redundant. Right now we've got our own physical servers at a colo, running a VMWare cluster connected to an EqualLogic SAN. It's a LAMP setup. We want to set up a second site, either for load balancing or for as an active/passive failover (I think we've been leaning towards the latter, but no decisions have been made).
On the drawing board, we came up with what we thought was a simple solution. ourdomain.com resolves to 126.96.36.199, which is the IP address of a load balancer, or a failover service or a something like apache's reverse proxy.. where requests come in to it and it forwards the requests to the appropriate data center. That way if data center A goes down, we simply change the load balancer to send all requests to data center B.
We have failed at being able to find ANYONE that offers this type of service. Everyone we ask about it (like X0 and L3) say they don't really know if we'll find something like that. Our end goal is to have redundancy between two sites to minimize downtime, whether it be hardware failure or an entire data center goes offline due to natural disaster. We describe this set up to all sorts of vendors and none are familiar with any such service..
The best idea we've encountered is using failover DNS. We currently use dnsmadeeasy.com, and if their monitors detect that site A has gone dark, they'll change DNS to resolve to the IP of site B. We've done some tests and even with our TTL at 1 minute, it took around 15 minutes on average for DNS servers to get the change, while some DNS providers we queried overseas (like Australia, which is important to us) took almost an hour to make that change. That's not good enough.
So what am I missing?
- Does a hosted failover solution exist? Why do all these big name companies act like they've never heard of such a concept before when it seems like it should be fairly common?
- Is mod_proxy something that will work for us? If so, can you set up a cluster of apache server's doing mod_proxy so IT doesn't become a single point of failure?
- Is there a better solution for redundant sites that you could suggest?