I would like to switch the DNS of our website without any service disruption
The server IP stays the same.
Usually it takes 24-48 hours to update the whole internet.
Is it possible to have both DNS work in parallel?
Important Note by JamesRyan:
Bear in mind that some DNS servers do not respect low TTLs and cache anyway. Expect some overlap.
^ this exactly is quite a problem.
I changed the DNS of our website to another Provider (bluehost which seems to be broken and quite often shows their ads page instead of our site) so I switched back to the old original DNS after ~2 hours.
The server's IP remained the same, so I hoped to not get any service disruption, because both DNS show the same server.
Now 24 hours later 30% of the internet still uses the broken / wrong provider (bluehost), which is not referenced in the whois. (concerning to Pingdom + several user report that they can't visit us)