Changing DNS Servers without Disrupting Service?

how to...?

[espeed]

What is the best way to change DNS servers without disrupting service? I thought that the servers that were slow to update would use the old DNS, and the updated servers would use the new DNS. Is this true?

[mcavic]

As long as your old and new DNS servers are all functional, you can update the domain and there won't be any disruption.

Yes, during the transition, some sites will see your old servers and some will see the new.

[moltar]

Technically all servers should follow TTL (Time To Live) record in your NS zone file. If they don't then consider them broken and you can't help it anyways. Most of them do though.

Said that, if you change your TTL to a very short period, like 1 minute. Then wait, make no changes for the period of your previous TTL value (to let it expire). Then change the NS servers. Technically you should have no downtime, or not more than 1 minute anywyas. The new DNS servers should have longer TTL (not 1 minute).

Note: If you have an extremely busy site, then this might be a problem, because your DNS server will be hit way too often and may crash.

[nativenewyorker]

If you run any type of forum or similar interactive service on your site, you will have problems as some people will be posting to the old server and some to the new server.