You can use two or more DNS providers, but if you do try not to list more than two name servers from any one provider when you delegate. You should also take care to do the same in your own zones "NS" record set. Some providers don't let you change the NS record set, so avoid those providers.
The reason for this is that resolvers will generally try at least three different name servers before giving up, so if you have three or more from a single provider that may not help.
There is also a big caveat to consider: once you use two more providers, whenever you need to make rapid DNS changes for your own availability reasons you will need to wait for the slowest-to-update provider.
Comments
You can use two or more DNS providers, but if you do try not to list more than two name servers from any one provider when you delegate. You should also take care to do the same in your own zones "NS" record set. Some providers don't let you change the NS record set, so avoid those providers.
The reason for this is that resolvers will generally try at least three different name servers before giving up, so if you have three or more from a single provider that may not help.
There is also a big caveat to consider: once you use two more providers, whenever you need to make rapid DNS changes for your own availability reasons you will need to wait for the slowest-to-update provider.