I need to host my website on multiple servers so that if my main server goes down then the backup server will start working.
My main server has a static IP address on which the site is currently running. I want to setup alternative hosting on Godadddy so that if the main server is down then the Godaddy hosting starts working on the same static IP.
Is it possible?
What you might want to achieve is a LOAD BALANCING/CACHE infrastructure. There are several ways to do this. What you have to decide first is how to implement it and where will your Load Balancers be hosted.
Option #1 - Load Balance using DNS Round Robin
Technically not Load Balancing in the most real sense of the term. You can achieve this by adding 2 or more A records in your DNS, pointing to the same domain with different IPs for each entry. So use your current Static IP and use GoDaddy's IP on the second record (if GoDaddy gives you an IP).
The limitation with this one is that it does not systematically check the most available server and send the request there. It simply randomly sends a request to the an IP on your DNS record. This means that it is still possible that a request would be sent to a down Server.
Option #2 - Implement HA Proxy or Nginx to Load Balancers
To explain is a bit long. You need to do reading here. But this is highly reliable. With this kind of system, your Load Balancer can check what is the most available server and send the request there. So it will not send a request to a server that is down. At the same time, you can configure it to avoid sending request to a server that's busy.
Option #3 - CloudFlare (Free)
CloudFlare can cache your files and show the cached copy if your site is down. Depends on your need and the type of site your running. The cache is not 100% the best on the Free package but works great. The paid packages cache better.
Some rootserver provider offer routable ip adresses (failover ip); that way you can set up two servers prepared to use the same routable ip address (additional to their static primary ip). To keep both servers synced you may use a network file system like drbd and/or db replication. When the primary server goes down, you can automatically reroute the domains ip address to the secondary server.
This will probably not be offered by your provider in mind, but is the only solution I know that works with only two servers. Failsafe load balancing requires 3 servers at least.
If a short downtime would be acceptable, you may instead set a very short ttl to the a-record of your domain(s), e.g. 5 minutes, and update your dns record appropriately to point to the "active" server.
