This works for simple DNS configurations, but gets a lot more complicated if you use DNS based load balancing, any kind of automated changes to DNS, DNSSEC, etc

This works for simple DNS configurations, but gets a lot more complicated if you use DNS based load balancing, any kind of automated changes to DNS, DNSSEC, etc. Also, I would absolutely make sure you have a way to keep records in sync. Updating the backup should be an automatic part of updating any records.