Setting up a mirror site and directing traffic to it in case the primary site goes down?

Question

I've had a rapidly increasing stream of traffic to my site and would like to set up a sort of mirror site so that if the main site was down for whatever reason--maintenance, hackers, whatever--traffic would be directed to the mirror site. I've heard about setting up mirror sites before, but I'm not too sure what would be needed to redirect traffic to the mirror site if the main site was down. Would there be some kind of notation in my IP address for my primary domain, JesusFreak.com, for traffic to be redirected to, say, JesusFreak.net, if the server for JesusFreak.com was down? How exactly does this work with mirror sites, and what would it take to set one up?

I'm actually worried more about hackers than traffic per se, Tracy. That's why I'd like to create a redundant site in case hackers hit one. I know that high-profile sites are usually bigger targets for trouble than smaller ones, which is why I'd like to have a contingency plan now rather than later. :-)

Answer 1

Well sounds like you may need more load balancing than a mirror? Those are actually two different items but both can be helpful

To setup a mirror - assuming you are on Linux
http://www.howtoforge.com/mirroring_with_rsync
or
http://linuxgazette.net/104/odonovan.html
not to hard and quickly duplicates your site.

The fall over part is a little more complex.
but you can use the "secondary nameserver" trick mentioned here.
http://www.samag.com/documents/s=9364/sam0204e/sam0204e.htm
but you need to see why that probably isn't very logical
http://www.webhostingtalk.com/showthread.php?t=353114
there are some work arounds to attempt to get past NS caching
http://www.presttun.org/kare/DNS/DNS-LB-FT.pdf
dont know if that works, havent tried it.

Or there are services designed to do this
http://www.simplefailover.com/default.aspx
or
http://www.neustarultraservices.biz/solutions/traffic.html?gclid=CICM-Lun3o0CFQEtZQodhnwNmQ
or
http://www.autofailover.com/
The first one is more affordable than the second which is less than the third.

I am sure there are other ways to do this also.
You will need to be sure your databases stay in sync also.

Add
The nice part about an rsync system is that it can move either direction. So if you main site was corrupted a simple rsync to replace all files restores the original site within minutes!

Answer 2

This link may give you some good ideas.