Redundant Servers ---?

backup server with second hosting company.

[nkakar]

hey guys, im sure this has been asked before, but i cant find out any solid answers. I want to setup my website in such a way that if the dns of my website or even my hosting company goes down for whatever reason, i want the site to be asking for pages through a second hosting company that has the same exact pages linked with their dns's. I tried this once by adding the dns' of the second hosting company on my domain registered with networksolutions, but what happened was soemthing i couldve never imagined. the backup site on the second hosting company instead of using the second hosting company and its dns's for backup, was sharing the traffic with my current hosting company and its dns's. i dont know how to figure this out in an inexpensive way. are there any softwares i can get to fix this issue? right now i would have to change the dns' on my domain manually through networksolutions which takes 6 hrs to propagate across the internet... ive been researching this issue for over 2 months now and this is the farthest ive been.! any advice would be appreciated!

thank you! :)

[digitalv]

It seems like your question only pertains to DNS, which is really only half. If your present host were to go down, what good would a second DNS with another ISP do? You would need EVERYTHING on the second network also, not just DNS.

I've accomplished this in the past with switches that support load balancing, or even two F5 BigIP Load balancers and replicated data. Lets assume in a basic setup, you have one machine running DNS and your website in Location A, and a "mirror" of that in Location B.

What you would do is put a load-balance-capable switch or a BigIP in each data center and assign your IP addresses to it (use internal IP's for your machines that are behind the load balancer). Configure BOTH load balancers to always send traffic to "SERVER A" and if "SERVER A" is down, send traffic to "SERVER B".

Your DNS entries will point to the load balancer IP's, not the server IP's - the load balancer will send the traffic where it's supposed to.

Then, at the registrar, set up your two name servers pointing to each of the two DNS IP's. This way no matter what DNS the user happens to pick up, they will ALWAYS be sent to "SERVER A" unless Server A is down, in which case they'll be directed to SERVER B.

In order for this situation to fail, you would have to have a hardware or connectivity issue simultaneously in both data centers.

[nkakar]

Hey DigitalV,

thanks for your response. Im sorry I failed to say that I already have the replicated data on both the hosting companies. i dont quite know what "load-balance-capable switch or a BigIP" is, but I'll try to find out. Im not sure if I will be allowed to do this in the backup hosting company because my because server is a shared server from what I know even the IP is actually being shared by multiple domains unlike my primary which is dedicated... any suggestions!

thank you sooooooooo much, I really appreciate it!

Nick

[nkakar]

sorry, another question:

is loadbalancer a software or a hardware and can it be easily bought off the shelf?

[digitalv]

There are such things as load balancing software, but I wouldn't recommend any of them. A Hardware solution is the way to go.

Load balancing is a switch or device's ability to "middle-man" traffic and determine the final destination. Say you have multiple servers that all run the same website. Your load balancer would have an IP address, and that's the IP that would be assigned to the DNS. When someone hits that IP or any domains that point to it, the load balancer determines which server of the 10 to send the data to.

F5 is a company that makes load balancers, and BigIP is one of their products. You can configure these any number of ways ... automatically divide the traffic evenly among the servers you've configured, or have it always send traffic to one specific server and if it goes down start sending it to another one.

Check out F5's site snipped or Network Liquidators for good used ones snipped. Also check out ebay, you can find deals there too but you'd be on your own for configuring it.

[edited by: DaveAtIFG at 5:13 pm (utc) on April 5, 2004]
[edit reason] Commercial URLs removed [/edit]

[nkakar]

DigitalV,

YOURE A GENIUS!

Thanks a lot man!