Creating Cheap Fault-tolerant Web hosting via DNS and BIND

[mandy]

The words "fault-tolerant Web hosting" bring to mind hosting centers with multiple redundant power supplies, complex networking, and big bills. However, by taking advantage of the underlying fault-tolerance of the Internet, you can get a surprising level of reliability for little cost.

There's a worrying number of things that can go wrong and take your Web site down. For instance, if the power supply goes down in your hosting center, then all the routers, switches, and servers go down too. Finally, any router, switch, server, firewall, or other piece of network infrastructure can fail.

Large sites usually have multiple Internet connections into their server farm via separate leased lines following independent paths through different telephone exchanges. To defend against power outages, they have incoming power feeds, uninterruptible power supplies, and generators. Finally, they carefully design their network so that there are always multiple routes between the servers and the Internet, so that any single cable or piece of equipment can fail without causing a problem.

An easier way of getting nearly the same level of redundancy is to install two servers at different hosting centers, with different Internet service providers (ISP) -- but there's a problem with that...

full article: http://www.linux.com/article.pl?sid=07/05/07/1442254