If I need to move a site to another server because of an expected downtime of over 12 hours is it best to just add the new DNS records and leave the old ones in?

We might move the site back to the old server but we are not sure right now, we just can't afford to have the downtime. So my question is it okay too have 4 dns records for both hosts/nameservers or is there a better way to do this?

Shawn

Just adding the new records would result in DNS load balancing (round-robin) so wouldn't do what you want. You should remove the old records and put the new ones in so all traffic is directed to the new server.

Once you've changed them, don't forget that they'll be cached, so unless you plan it and change the expiry time in the zone file you'll have to wait aroud 24 hours for the old server to stop getting hits.

If the servers are in the same datacenter, you may be able to simply move the IP address ;)

And yes, dannyboy is right, you need to change the dns details altogether, allthough you could have two MX records, the second server could have a higher number, and then mail would get delivered to which ever machine could take it :)

If you are planning a move, think about making your cache values lower, perhaps down to 1 hour, so when you change, the caching will take upto 24+1, instead of 24+24 hours ;) (of course some cache's last more than 24 hours, or whatever they are configured to :rolleyes: )

Cheers,
Infinite :D