backup if site is down?

[emma]

I am looking for a way to ensure that users can still use my site if my current host fails or is not available at any given time.

I had assumed(wrongly it turns out) that the way to do this was to add 2 extra namservers to the dns records for my domain name, making a total of 4. i.e. 2 for my current host and 2 for a backup(different) host. So if the first two did not work, the other 2 would automatically be tried. I have been told this will not work.

What is the best way to achieve this? I want to use my current host if it is available. If, and only if, it cannot be reached the backup host should be used?

[Ecco]

Why do you need 2 hosts? If reliability is paramount either spend more on a better host and/or add another server and load balance them. Short of their backbone falling over, that should leave you pretty resilient.

[emma]

Thanks for the reply Ecco.

Reliability is important. Even the best hosts experience some downtime though. So is load balancing the only option? If so what's the best(and cheapest) host for that? Would any suit multiple domains?

Am I right I would only have to upload my site once for this to wrk, and not once on each server?

[Ecco]

Load balancing isn't the cheapest option as you need to own 2 servers, but you don't need to maintain them separately as you can get the host to sync them.

Perhaps a lower cost option would be too take a single server solution with a good SLA so that you can guarantee very high uptime, fix times, etc. For example, if you could guarantee downtime at less than x% and downtime to last no longer than xMinutes for problem group A, and xMinutes for problem group B, would that solve your concerns?

Would any suit multiple domains?

On your own server, you can have all the domains you want. My personal reccomendation would be to take a look at Positive Internet (http://www.positive-internet.com) who offer some reasonably priced solutions to do these jobs.

[Aquanuke]

Round Robin DNS is the best way to do it, although pretty expensive.. best to Google it.
http://www.google.com/search?q=round...utf-8&oe=utf-8

Although the cheapest way would probs be using
http://www.zoneedit.com/

Also I know asuk offer the works if your pocket can handle it.
http://dedipower.com/d/prod-advanced/

[emma]

Thanks for all replies Ecco and Aquanuke. Gives me a few things to think about-probably go for round robin or load balancing.

Just out of interest, and to satisfy my own curiosity why doesn't what I said in my first post work? If this is so, why specify two nameservers for most domains, and looking at whois why do some companies specify 3-4 different ones. I always thought the 1st was looked at - if no response then the 2nd etc. But this is not the case, and I don't quite understand the reason

Another quick question: is there any real performance difference if I choose a US host for a UK site, as opposed to a UK one. I understand there will be more 'hops' but will the average user notice any difference?

[Aquanuke]

Theres alot of googd threads regarding what your looking to do at rackshack.

Have alookie at

http://forums.rackshack.net/showthre...ng+nameservers

DNS is a complicated affair.

[Supercod]

Originally posted by emma
If this is so, why specify two nameservers for most domains, and looking at whois why do some companies specify 3-4 different ones.

It can be for a number of reasons, it could be they are hosting 100's of thousands of domain name and need them to cope with the load, because every time a domain name is typed in, a DNS server is asked where it is hosted (i.e. what IP to send the traffic too).

One of the thing I have done is to put my first name server

ns1.internetbackbone.co.uk in the UK

and my second one

ns2.internetbackbone.co.uk in the USA

As I runs servers in London, New Jersey and Britsih Columbia it's important for me that all sites don't depend on one location being up at all times.. so say my USA side was wiped off the map, I could still run my UK and Canada operations and vice versa.

We are looking at getting a 3rd DNS server and also hosting that on a completely different network with a completely different host name, adding yet one more little bit of reliability to me network of sites.

[Supercod]

Oh and I also agree with Aquanuke, Round Robin DNS is one of the best ways to do it, means your not tied to having all your servers at the same data centre also, because you should also be controlling your own DNS you can for example set the records time to live very low and also be able to remove a bad IP when it goes down so minimising your down time.

This type of set-up is not cheap in the slightest, when I hear affiliates who make 10's of thousands a year trying to pay £50 a month for hosting I just laugh. Try paying out £1,000+ a month for hosting and see what you get

But I fear that until Internet 2 comes out, we will be stuck with downtime happening.. if it can happen to Microsoft, Yahoo and Google, it can happen to anyone.