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kwolbert_ITFlag for United States of America

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Web server failover using dns

I currently have two web servers. Each located on different ISP.
Seeing how DNS round robin only provides load balancing and not redundancy,
I wanted to go with another option. I found this article from ‘wight-hat.com ‘that suggested
to put the put the DNS service on each web server.  And modify the name servers on the
original DNS server. Name Server 1 will point to Web server 1 and Name Server 2 will point
 to Web Server 2. In this Case if the DNS is unable to reach it’s Name Server 1
“Also the Web Server 1” then it will try to contact the Name Server 2 “Also Web Server 2”.
 All hosts (A records)  will supply the correct IP address to contact the available web server.
 Is this a viable option?
What are the pro and cons to doing this?

 The article can be found here
http://www.wight-hat.com/guides/hosting6.html
PS Web server runs on Windows 2003 IIS 7.0
Thanks in advance
Keith

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rfc1180
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>http://www.wight-hat.com/guides/hosting6.html

DNS Global Load Balancing is a great method; however, the method they use: http://www.wight-hat.com/guides/hosting6.html

I would not recommend(I would not use their method in my environment!); you need a solution that contains healthchecks for the servers; if you want a reliable, efficient and scalable load balanced environment, then you need s system specifically designed for that. The method they use still imposes delay due to the necessary re-query.

Some Vendors that offer DNS Global load balancing:

http://www.f5.com/products/big-ip/product-modules/global-traffic-manager.html
http://www.brocade.com/forms/getFile?p=documents/data_sheets/product_data_sheets/serverIronADX_DS_05.pdf
http://www.radware.com/Resources/dns_load_balancing.aspx

Billy
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ASKER

Thanks for the reply
But I am not really concerned with the load and the scalability.
Just the available of the servers.
This is really just a Hot Site.
Thanks
Keith
Well, I still stand by my solution; I would not offer any other solution besides a dedicated device that is designed for load balancing. Basically what they are doing is by passing what a dedicated load balancer is designed to do and also lowering the cost. You should always consider scalability in our design, I just would not have it any other way.

Good luck to you

Billy
But no load balance is required in this design for this is a Hot site, which sould only be used when the other is not available and adding a load balancing device is another point of failure

As always
Thanks for the reply
ASKER CERTIFIED SOLUTION
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rfc1180
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Only wanted to do it his way didnt want to try to help me in the way I asked
>Only wanted to do it his way didnt want to try to help me in the way I asked
Funny, you did ask: "What are the pro and cons to doing this?"
I gave you the pros and cons:

"efficient and scalable load balanced environment, then you need s system specifically designed for that. The method they use still imposes delay due to the necessary re-query."

Billy
You right about the way I worded the question. How I should have asked was “Would this work”.
I understand what you described and how it would work. The problem that there is no more budget for this project. I appreciate you taking the time you try to help me on this subject.
Thanks
Keith