It's not possible. If you want a thorough answer, read Five nines: Chasing the Dream.
Some hosting vendors claim to offer 100% up-time (even less possible than the practically impossible 99.999% up-time!) to get the sale, but we prefer to be up-front and honest so as not to set false expectations.
Even if it were possible for us to guarantee 100% up-time on our network and servers, we have no control over the internet. Think about it:
- Has your local network at work ever failed?
- Has your home internet connection ever failed?
- Have any of the myriad of servers and routers between you and some other server on the internet ever failed?
Depending on how much time you spend online, you might not have noticed all three failing - but they do. Just as they are outside your control, they are also outside our control.
We can't guarantee the internet - nobody can. Even if the Internet was completely "Carrier Grade", that would still only be 99.999% up-time and even then there are plenty of documented cases of entire countries losing internet connectivity: example 1, example 2, example 3.
Added by