NS Zone Records and Name servers when using Secondary DNS provider

Question

I am attempting to setup Secondary dns with a well known provider. The goal is to have DNS served from 2 providers. The secondary DNS provider will mirror records from the primary dns provider so I only have to update them in one place.

I am reading through their instructions and need clarification.

Step one is:

Add NS records for our nameservers in your domain's zone file. Our name servers are:

I am assuming this means on the current DNS's provider I add the records to their dns zone/system file. If I do this ahead of time will this cause any downtime/issues? Or is this is simply a pointer record?

Step 2 is:

Add our name servers, as listed above, to the delegation of your domain through your registrar

Does this mean I go to my domain register and add their name servers to the end of my name servers like what I did for my primary DNS provider?

Answer 1

Neither of those steps accomplishes the mirroring of your records into the new provider's servers. You need that to be completed before you delegate to the new servers.

I am assuming this means on the current DNS's provider I add the records to their dns zone/system file.

Correct.

If I do this ahead of time will this cause any downtime/issues?

Well.. not really - if the new servers don't have the records yet, then this will technically be an inaccurate record - but the delegation at the registrar is what will really get requests sent to the new servers.

Does this mean I go to my domain register and add their name servers to the end of my name servers like what I did for my primary DNS provider?

Correct. This step is what will cause the new provider's servers to be used by lookups, and shouldn't be done until you've confirmed via a manual lookup that the new provider's servers are accurately serving requests for your domain.