Nameserver Question - two servers

[nurseryboy]

Hey guys,

I have two servers being set up now, and am trying to figure out which way to set the nameservers up. One server is on the East coast, and one is on the West coast. I would like to have it so if one goes down, the other one can pick up the site(s).

The East coast server will have ns1.domain.com and ns2.domain.com, and the West coast will have ns3.domain.com and ns4.domain.com. I will be setting ns1 & ns2 to point to the primary IP & secondary IP of the East coast server , and ns3 & ns4 to point to the IP's of the West coast server, through the domain registrar.

My question is.. how should I set up each website's NS for this?

For an East coast website, should it be:

ns1.domain.com
ns2.domain.com
ns3.domain.com
ns4.domain.com

or can I do just:

ns1.domain.com
ns3.domain.com

And visaversa for the West coast websites:

ns4.domain.com
ns3.domain.com
ns2.domain.com
ns1.domain.com

or:

ns3.domain.com
ns1.domain.com

Or am I going about all of this totally the wrong way?

Thank you very much.

Matthew